Condition Analysis
AI-powered assessment using site data and 14-day weather history
The dolerite at Crag Lough has had roughly a day of drying since the last light rain on May 5th (1.3mm), and today is largely dry through the afternoon with moderate wind aiding surface drying. However, the north-facing aspect, high humidity, and light showers forecast from late afternoon onward mean conditions should be visually assessed on arrival — the rock may still hold residual dampness in sheltered corners.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Crag Lough is north-facing at 260m on the Whin Sill ridge, so it receives virtually no direct sun and relies almost entirely on wind for drying.
- Peregrine falcons nest here in spring — check the BMC RAD for any current seasonal access restrictions on specific buttresses before visiting.
- The crag sits above the lough (lake) and surrounding boggy moorland, which can contribute to localised humidity and seepage from the grassy crag top, especially after the wet April (52mm in 28 days).
- Loose blocks and freeze-thaw debris at the base remain a hazard; overnight lows have still been dipping near or below freezing recently (−0.5°C on April 24th, 1.0°C forecast May 12th).
Warnings
2
- The dense black dolerite becomes extremely slippery with even a thin film of moisture — test friction carefully before committing to any route.
- Peregrine nesting restrictions may be in effect on certain buttresses; verify access via the BMC RAD before climbing.
Reasoning
The last significant rain was 15.4mm on May 3rd, followed by a dry day on May 4th, light rain (1.3mm) on May 5th, a fully dry day on May 6th, and today is mostly dry — for non-porous dolerite this is generally sufficient surface drying, but the north-facing aspect and persistently high humidity (81% average over 7 days) may leave residual dampness in sheltered areas.
Moderate winds (15–24 km/h) from the south today help dry the exposed face, but the north aspect means no solar heating at all; the combination gives reasonable but not rapid drying for the hard, non-porous surface.
Dolerite does not suffer structural weakening when wet, but active freeze-thaw at the crag base loosens blocks — overnight lows have been close to freezing recently, so check for fresh rockfall debris.
Early May is transitional — days are lengthening and temperatures are mild, but the persistent easterly/northerly airflow has kept conditions cool and damp; peregrine nesting restrictions may apply to certain buttresses.
Contributing Factors
6
Whin Sill dolerite absorbs virtually no moisture, so structural damage from climbing on damp rock is not a concern — the issue is purely friction.
The crag receives no direct sunlight, removing the most effective drying mechanism and leaving wind as the sole means of surface evaporation.
The high, exposed position on the Whin Sill escarpment means persistent wind compensates somewhat for the lack of sun, accelerating surface drying.
15.4mm fell on May 3rd and 1.3mm on May 5th, but the intervening and subsequent dry hours with moderate wind should have cleared most surface moisture from the non-porous rock.
Average humidity of 81% over the past week and the lough below create a persistently damp atmosphere that slows evaporation and can leave a thin moisture film on the dense black rock.
A total of 0.6mm is forecast from late afternoon onward (16:00–23:00), limiting the usable climbing window to the morning and early afternoon.
Recommendations
3
- Climb during the dry window this morning through early afternoon (before ~16:00) when humidity is lowest and winds are moderate, and visually check the rock surface for dampness before committing to routes.
- Check the BMC RAD for current peregrine nesting restrictions at Crag Lough — spring closures may affect specific buttresses.
- Be vigilant for loose blocks and fresh freeze-thaw debris at the crag base, and test friction carefully on the first moves of any route as the dense black dolerite is extremely slippery when even slightly damp.
Previous Analyses
Marginal — Assess Conditions
72%
2 days ago
The dolerite should be largely dry today after 1.3mm of light rain on May 5th followed by a full dry day with dropping humidity and moderate east wind; however, the north-facing aspect and high ambient humidity over recent days mean some seepage or residual dampness in sheltered corners is possible. Conditions this afternoon look promising but a visual check on arrival is warranted.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north-facing aspect receives virtually no direct sun in spring, so any seepage from the grassy Hadrian's Wall ridge above can persist in gully lines and recesses for longer than expected.
- Peregrine falcons nest at Crag Lough in spring — check BMC RAD for current seasonal restrictions before visiting, as sections may be closed.
- The exposed Whin Sill ridge catches strong winds from most directions, which greatly aids surface drying on this non-porous rock but also makes conditions feel much colder at 260m.
- Loose blocks and freeze-thaw debris at the crag base remain a hazard in early May, especially after the overnight near-frost temperatures recorded recently.
Warnings
2
- Dolerite is extremely slippery when even slightly damp — test friction carefully on lower holds before committing to routes.
- Check peregrine nesting restrictions; access to parts of the crag may be prohibited during the spring breeding season.
Reasoning
The last meaningful rain was 1.3mm on May 5th, with today completely dry and humidity falling to ~47% by afternoon — surface moisture on non-porous dolerite should have evaporated, though seepage from saturated ground above may linger on the north face.
Moderate east wind (~15 km/h) and low afternoon humidity today provide reasonable drying conditions, and the non-porous dolerite sheds surface water quickly, though the north aspect receives no direct solar radiation to assist.
Dolerite does not suffer structural weakening when wet; the main hazard is loose blocks at the base from ongoing freeze-thaw activity during the cool spring nights near 0°C.
Early May at 260m with overnight lows near freezing means residual ground moisture and possible morning frost; peregrine nesting restrictions may apply and should be checked before visiting.
Contributing Factors
6
Only 1.3mm fell on May 5th, with today fully dry — minimal surface water to shed from non-porous rock.
The north face receives no meaningful direct sunlight in spring, removing solar drying as a factor and allowing seepage to persist.
Humidity falls from 81% overnight to 47% by mid-afternoon, actively drawing residual moisture off exposed rock surfaces.
Whin Sill dolerite absorbs negligible water, so surface drying within hours of rain clearing is typical.
17.2mm in the last 7 days and 81% average humidity mean the surrounding ground is saturated, feeding seepage lines from the grassy ridge above.
Steady ~14 km/h east wind across the exposed ridge helps strip surface moisture efficiently.
Recommendations
3
- Plan to climb this afternoon when humidity is at its lowest (~47%) and the rock has had the longest drying window since yesterday's light rain.
- Check for seepage lines and wet patches on arrival — particularly in gullies and at the base of buttresses where runoff from the grassy ridge above collects.
- Verify current peregrine nesting restrictions via the BMC RAD before visiting, as sections of Crag Lough may be closed in spring.
Marginal — Assess Conditions
68%
3 days ago
The heavy rain on May 3rd (15.4mm) was followed by a dry day yesterday and only trace precipitation today (0.3mm). Being non-porous dolerite, the rock itself won't have absorbed moisture, but the north-facing aspect, high humidity overnight (near 100%), and cool temperatures mean surface dampness and residual seepage are plausible — climbers should check conditions on arrival before committing.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Crag Lough's north-facing aspect receives virtually no direct sun in spring, meaning surface moisture from overnight condensation and seepage persists well into the day — the rock may feel greasy even when rain hasn't fallen.
- The Whin Sill ridge is fully exposed to wind, which is the primary drying mechanism here; today's moderate northerly wind (~21 km/h) is helpful but blows directly onto the face, potentially carrying moisture.
- Active seepage lines from the boggy ground above Hadrian's Wall can weep for days after the 15.4mm event on May 3rd, creating localised wet streaks even when the main face appears dry.
- This is peak peregrine nesting season (April–June) — check for any active nesting restrictions on specific buttresses before climbing, and consult the BMC RAD for current closures.
Warnings
3
- Dolerite becomes extremely slippery when damp — if any surface moisture or greasy film is visible, do not climb.
- Overnight temperatures near 0°C may produce thin ice on holds in shaded areas early in the morning — avoid early starts.
- Check for peregrine nesting restrictions; some buttresses may be closed through June.
Reasoning
The 15.4mm rainfall on May 3rd is the key event; while dolerite doesn't absorb water, surface moisture and seepage from saturated ground above likely persisted through yesterday's overcast conditions and into today's cool, humid morning.
Yesterday afternoon saw improving conditions (humidity dropping to ~60%, moderate westerly wind), providing reasonable drying, but overnight humidity returned to near-saturation levels (96–98%), likely depositing fresh condensation on the cold north-facing rock surface.
Dolerite does not suffer structural weakening when wet, but loose blocks at the crag base are a persistent hazard — freeze-thaw is less active now in May but remains relevant given overnight temps near 0°C.
Early May brings lengthening days but the north aspect still receives minimal direct sunlight; overnight temperatures dropping to near freezing (1.5°C today, forecast 0°C tomorrow) can cause thin ice or heavy condensation on rock surfaces.
Contributing Factors
7
15.4mm fell on May 3rd — while the rock is non-porous, this saturated vegetation and soil above the crag, feeding seepage lines.
Whin Sill dolerite does not absorb water and dries rapidly once surface moisture evaporates — no structural damage risk.
Humidity reached 96–98% overnight with temperatures dropping to ~4.5°C, likely depositing condensation on the cold north-facing rock.
The exposed ridge position and moderate northerly wind (~21 km/h) today will help strip surface moisture through the afternoon.
The crag receives negligible direct sun, so drying relies almost entirely on wind and ambient temperature — both modest today at 9.6°C max.
A small 0.2mm shower is forecast around midday and 0.1mm around 19:00 — trivial amounts but enough to re-wet the surface briefly.
The forecast shows virtually no rain for the next five days, with dropping humidity — conditions will steadily improve.
Recommendations
3
- If visiting today, wait until mid-afternoon when humidity drops below 70% and wind has had time to dry the rock surface — visually inspect for damp patches and seepage before climbing.
- Tomorrow (May 6th) looks significantly better with 0mm precipitation forecast, 63% humidity, and a further dry day behind it — consider delaying if conditions today look marginal.
- Check for active peregrine nesting restrictions on specific buttresses via the BMC RAD before climbing — this is peak nesting season at Crag Lough.
Marginal — Assess Conditions
65%
4 days ago
Yesterday's heavy rain (15.4mm) saturated the crag, but today is dry with improving conditions through the afternoon — humidity drops to the mid-50s and a westerly breeze picks up. Being non-porous dolerite, the rock surface should dry within hours once conditions improve, but the north-facing aspect and overnight near-saturation humidity mean residual dampness is likely this morning; an afternoon window from around 13:00–19:00 looks most promising but needs on-the-ground verification.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Crag Lough is north-facing at 260m on the Whin Sill ridge, so it receives no direct sun — all drying relies on wind and ambient temperature, making the afternoon westerly breeze (15–18 km/h) the main drying mechanism today.
- Seepage from the saturated peat and grassland above the crag can persist for days after heavy rain, creating wet streaks down the face even when the rock itself is surface-dry.
- Peregrine falcons nest at Crag Lough in spring — climbers should check for current nesting restrictions (typically Mar–Jun) before approaching the buttresses.
- Loose blocks at the crag base are a perennial hazard; yesterday's heavy rain and recent freeze-thaw cycles (overnight lows near 0°C in recent weeks) may have loosened material further.
Warnings
2
- Dolerite is extremely slippery when damp — if holds feel greasy on touch-testing, do not climb; the friction loss is sudden and severe.
- Loose blocks at the crag base may have been further destabilised by recent freeze-thaw and heavy rain — approach with caution and wear a helmet.
Reasoning
15.4mm of rain fell yesterday with near-100% humidity throughout, and overnight humidity remained above 95%, so the rock surface was certainly wet through this morning and residual moisture films are likely in sheltered areas.
Today's westerly breeze (building to 15–18 km/h) and falling humidity (down to ~55% by mid-afternoon) should strip surface moisture from the exposed dolerite within a few hours, but the north-facing aspect means no solar heating to accelerate evaporation.
Dolerite does not weaken when wet, but loose blocks at the crag base may have been destabilised by recent freeze-thaw cycles — overnight lows have repeatedly dipped near or below 0°C in recent weeks.
Early May at 260m in Northumberland brings cool temperatures and short effective drying windows; peregrine nesting restrictions may be active and should be checked before climbing.
Contributing Factors
6
15.4mm fell on May 3rd with near-100% humidity all day, thoroughly wetting all rock surfaces and saturating the ground above the crag.
No rain today, humidity dropping from 96% overnight to ~55% by mid-afternoon with a building westerly breeze of 15–18 km/h across the exposed ridge.
Whin Sill dolerite does not absorb water and dries from the surface outward, typically within hours of rain stopping given adequate wind.
The crag receives no direct sunlight, so drying relies entirely on wind evaporation and ambient temperature, slowing the process compared to south-facing venues.
Saturated peat and grassland on the Whin Sill plateau above the crag will generate seepage lines down the face that persist well beyond surface drying.
The crag's high, exposed position on the Whin Sill escarpment maximises wind exposure, which is the primary drying agent for this north-facing venue.
Recommendations
3
- Target an afternoon climbing window from approximately 13:00–19:00 when humidity is lowest and wind has had several hours to dry exposed surfaces — visually and tactilely check holds before committing to routes.
- Avoid routes with known seepage lines or drainage gullies, as these will remain wet for much longer after yesterday's heavy rain.
- Check current peregrine nesting restrictions for Crag Lough before approaching — spring closures are common at this venue.
Do Not Climb
90%
4 days ago
Today has seen 15.5mm of heavy rain with 96% humidity — the dolerite will be thoroughly wet and extremely slippery right now. Although whinstone dries quickly, the combination of ongoing saturation, north-facing aspect, and high humidity means surface moisture will persist through the day.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Crag Lough is north-facing at 260m on an exposed ridge, meaning today's heavy rain will linger on the rock surface longer than at sunnier, lower venues — there is virtually no direct sun to assist evaporation.
- The Whin Sill dolerite is notoriously slippery when wet: the dense, dark rock offers excellent friction when dry but becomes treacherously greasy with even a thin moisture film.
- Active freeze-thaw at crag bases is less of a concern in May, but overnight lows near 3–5°C combined with recent saturation mean loose blocks at the base could still be unstable.
- Crag Lough is a peregrine nesting site — in spring (typically March–June) climbers should check the BMC RAD for any active restrictions before visiting.
Warnings
2
- 15.5mm of rain today makes all routes dangerously slippery — do not climb on wet dolerite.
- Peregrine nesting restrictions may be active at this crag through June — verify with the BMC RAD before visiting.
Reasoning
15.5mm of rain today with 96% humidity means the rock surface is currently saturated with standing water and seepage in cracks and on ledges.
Despite the exposed ridge position offering wind-drying potential, the north-facing aspect receives minimal direct sun and today's NE wind at ~19 km/h combined with near-saturated air (96% humidity) will barely assist evaporation.
Dolerite does not suffer structural weakening when wet, but loose blocks at the crag base — a known feature of the Whin Sill — may be destabilised by heavy rain and freeze-thaw debris.
Spring conditions in early May at 260m in Northumberland are improving but still cool; overnight lows near 3–5°C slow drying, and peregrine nesting restrictions may apply at this site.
Contributing Factors
7
15.5mm of precipitation today has thoroughly soaked all rock surfaces, cracks, and ledges.
Near-saturated air prevents effective evaporation from the rock surface even with moderate wind.
The north-facing orientation receives virtually no direct sunlight, significantly slowing any drying process.
The exposed position on the Whin Sill ridge allows wind to strip surface moisture faster than sheltered crags.
Whinstone does not absorb water so only surface moisture needs to evaporate, enabling much faster drying than sandstone.
Dense black dolerite becomes extremely slippery with even a thin film of moisture, posing a serious safety hazard.
Crag Lough is a known peregrine nesting site and restrictions may be active during the March–June breeding window.
Recommendations
3
- Do not climb today — the rock will be wet and dangerously slippery; wait for tomorrow when dry weather and lower humidity should allow the dolerite to dry.
- Check the BMC Regional Access Database for any active peregrine nesting restrictions at Crag Lough before planning a visit.
- When conditions improve, test friction on lower holds before committing to routes — dolerite can retain a thin moisture film in shaded cracks and on north-facing surfaces even when it appears dry.
Do Not Climb
90%
4 days ago
Crag Lough received 17.2mm of rain today with 95% humidity and a NE wind blowing directly onto the north-facing crag — the rock will be thoroughly wet and extremely slippery. Even though dolerite is non-porous and dries quickly, conditions today are clearly unsuitable for climbing.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north-facing aspect means the NE wind today is driving rain directly onto the climbing faces, maximising surface saturation.
- At 260m altitude with sub-10°C temperatures and near-saturation humidity, evaporative drying will be negligible for the rest of today.
- Peregrine nesting season is active (spring) — climbers should check the BMC RAD for any current restrictions on specific buttresses before visiting.
- The exposed ridgeline position normally aids rapid drying, but today's persistent NE airflow brings moisture-laden air from the North Sea directly across the crag.
Warnings
3
- The dense black dolerite becomes extremely slippery when wet — friction loss on today's soaked rock would make climbing very dangerous.
- Peregrine nesting restrictions may be in effect on specific buttresses — check the BMC RAD before climbing.
- Loose blocks at the crag base are an ongoing hazard, potentially worsened by recent wet weather and freeze-thaw cycles.
Reasoning
With 17.2mm of rain today and 95% humidity, the rock surface will be saturated with standing water in cracks and on ledges, making the dense black dolerite treacherously slippery.
The NE wind is blowing directly onto the north face, bringing humid air rather than aiding drying; with only moderate wind speed (19.4 km/h) and near-saturation humidity, meaningful drying will not begin until conditions change tomorrow.
Dolerite does not suffer structural weakening when wet, but loose blocks at the crag base may be destabilised by water infiltration into joints, particularly after the wet spell of the last fortnight.
Spring conditions at 260m in Northumberland remain cool and slow-drying; peregrine nesting restrictions may apply to certain buttresses and should be checked before any visit.
Contributing Factors
6
17.2mm of precipitation today is a substantial soaking that will leave all surfaces wet and running with water.
Near-saturation humidity prevents any evaporative drying from occurring today.
The NE wind drives moisture directly onto the north-facing climbing surfaces rather than helping them dry.
Whin Sill dolerite sheds water quickly and does not absorb moisture internally, so it will dry rapidly once rain stops and humidity drops.
The exposed position normally accelerates drying, but today's wind is bringing moisture rather than aiding evaporation.
Max 9.8°C at 260m altitude provides limited thermal energy to assist drying.
Recommendations
3
- Do not climb today — the rock will be extremely slippery and dangerous after 17mm of rain at 95% humidity.
- Tomorrow (May 4) looks much more promising with dry weather, westerly winds, and dropping humidity — plan to assess conditions on arrival.
- Check the BMC RAD for current peregrine nesting restrictions at Crag Lough before visiting, as spring nesting season is underway.
Do Not Climb
90%
4 days ago
Crag Lough is currently receiving significant rain today (11.9mm) with 96% humidity and cool temperatures — the dense dolerite will be thoroughly wet and extremely slippery. The north-facing aspect and high humidity mean surface moisture will persist well into tomorrow.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Crag Lough is a peregrine nesting site and it is currently spring — check BMC RAD for active nesting restrictions before visiting, as seasonal closures may be in effect through June.
- The north-facing aspect receives minimal direct sun, so even though dolerite is non-porous, surface water and seepage from the crag top can linger in shaded corners and crack lines longer than on south-facing whinstone.
- The exposed ridge position means strong winds will help strip surface moisture once rain stops, but today's NE wind direction pushes moisture directly onto the north-facing rock face.
- Loose blocks and active freeze-thaw debris at the crag base remain a hazard — overnight temperatures have dipped near or below freezing recently (−0.5°C on Apr 24, −1.5°C forecast May 6), so check for fresh rockfall at the base.
Warnings
3
- The rock will be extremely slippery today — dolerite loses almost all friction when wet, creating a serious fall risk.
- Peregrine nesting restrictions may prohibit climbing at parts or all of the crag — verify via BMC RAD before travelling.
- Watch for loose blocks and fresh rockfall debris at the crag base following recent near-freezing overnight temperatures.
Reasoning
The crag is actively being rained on today with 11.9mm of precipitation and 96% humidity, so all rock surfaces will be thoroughly wet and running with water.
With a NE wind blowing moisture directly onto the north face and no sun exposure on this aspect, drying will not begin in earnest until the rain stops and wind shifts, likely not until tomorrow.
Dolerite does not suffer structural weakening when wet, but loose blocks at the crag base may have been destabilised by recent freeze-thaw cycles given near-freezing overnight lows.
Spring conditions in late April/early May at 260m altitude are marginal — temperatures are modest, humidity has been persistently high (84% average over 7 days), and peregrine nesting restrictions may apply.
Contributing Factors
7
11.9mm of rain today means all rock surfaces are saturated with running water, making the dense dolerite dangerously slippery.
Near-saturated air at 96% humidity prevents any evaporative drying and ensures persistent surface moisture.
Today's NE wind drives rain directly onto the north-facing crag, keeping the climbing surface wetter than a sheltered or lee-side aspect.
Whin Sill dolerite does not absorb water, so once rain stops and wind shifts, surface drying can occur within hours rather than days.
The highly exposed position on Hadrian's Wall ridge means wind will efficiently strip surface moisture once precipitation ceases.
A maximum of only 9.8°C today limits evaporative drying potential.
Spring is peak peregrine nesting season at Crag Lough and access restrictions may be in force — this must be checked before any visit.
Recommendations
3
- Do not climb today — the crag is actively wet and dolerite is dangerously slippery in these conditions.
- Check BMC Regional Access Database for peregrine nesting restrictions before planning any visit to Crag Lough this spring.
- Tomorrow (May 4) looks promising with dry weather and a westerly wind — but arrive prepared to assess surface conditions on the rock before committing, especially in crack lines and shaded areas.
Marginal — Assess Conditions
60%
5 days ago
Today is dry following only light recent precipitation (0.5mm yesterday, 2.5mm on April 27), and the non-porous dolerite should have shed surface water quickly. However, high humidity (88%), a north-facing aspect, and the exposed ridge setting mean residual dampness in seepage lines and sheltered corners is possible — a visual check on arrival is warranted.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Crag Lough is north-facing at 260m on an exposed ridge, so despite wind-assisted drying, it receives virtually no direct sun in spring and seepage zones can remain damp for extended periods.
- The crag sits above Crag Lough (the lake), which can contribute localised humidity and mist, especially on calm mornings — surface condensation on the cold black dolerite is common.
- Peregrine falcons nest here in spring; climbers must check the BMC Regional Access Database (RAD) for current restrictions before visiting, as sections of the crag may be closed.
- Loose blocks and active freeze-thaw debris at the crag base remain a hazard in April–May, particularly after the sub-zero overnight temperatures recorded recently (e.g. -0.5°C on April 24).
Warnings
2
- Peregrine nesting restrictions are very likely active at Crag Lough in early May — check BMC RAD before visiting or risk access being withdrawn.
- Rain (5.5mm) and near-saturated humidity (95%) are forecast for tomorrow (May 3); conditions will deteriorate sharply overnight.
Reasoning
The rock received only 0.5mm yesterday (May 1) and has had one full dry day today with moderate westerly winds; as non-porous dolerite, the surface should be largely dry, but 88% humidity today limits evaporation and north-facing aspects retain moisture longer.
Moderate winds (19–30 km/h) over the past two days on this exposed ridge will have stripped surface water efficiently, though the north aspect means no solar drying contribution and the high ambient humidity slows the final stages of evaporation from cracks and seepage lines.
Dolerite does not weaken when wet, but loose blocks from freeze-thaw are an ongoing hazard at the crag base — overnight lows have dipped below zero several times this month, maintaining the cycle.
Early May in Northumberland is transitional; days are lengthening but temperatures remain cool (averaging ~9°C this week), and peregrine nesting restrictions are likely in effect at parts of the crag.
Contributing Factors
6
Only 3.0mm in the last 7 days with the most recent meaningful rain (2.5mm) five days ago on April 27, giving ample time for non-porous rock to shed surface water.
Whin Sill dolerite does not absorb moisture and typically dries within hours of rain ceasing, making the single dry day sufficient for surface drying in most areas.
Today's 88% humidity significantly slows the final evaporation of residual moisture from sheltered cracks, seepage lines, and north-facing recesses.
The crag receives no direct sunlight, relying entirely on wind and ambient temperature for drying, which is a significant disadvantage in spring when temperatures are modest.
The high ridge position ensures consistent wind exposure that aids surface drying despite the lack of sun, with 19 km/h westerly winds today.
5.5mm of rain is forecast for May 3 with 95% humidity, meaning today may be the last dry window before a spell of unsettled weather through to May 7.
Recommendations
3
- Check the BMC RAD for current peregrine nesting restrictions at Crag Lough before setting out — sections are frequently closed February through June.
- Visually inspect the rock surface on arrival, particularly in seepage zones and sheltered corners; if any dampness is felt, the dolerite will be treacherously slippery and you should not climb.
- Take extra care around the crag base where freeze-thaw debris accumulates, and be aware that today may be the last viable climbing window before rain returns tomorrow.
Marginal — Assess Conditions
55%
6 days ago
Today saw 1.2mm of light rain on otherwise promising drying conditions after a largely dry spell from April 28–30. The dolerite surface should dry quickly in the moderate NW wind if rain has ceased, but the north-facing aspect and high humidity mean damp patches could linger — a visual check on arrival is essential before committing to climb.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Crag Lough is a peregrine nesting site and April–June restrictions may be active on certain buttresses — check the BMC RAD database before visiting.
- The north-facing aspect receives virtually no direct sunlight in spring, so seepage lines and sheltered corners between buttresses can remain damp long after the exposed faces have dried.
- The crag sits on the Whin Sill ridge and is extremely exposed to wind from all directions, which greatly aids surface drying on the open faces even without sun.
- Loose blocks at the crag base are a perennial hazard exacerbated by recent freeze-thaw cycles — overnight lows have dipped below zero several times this month.
Warnings
2
- Peregrine nesting restrictions are likely active — verify access status on BMC RAD before visiting.
- Conditions are forecast to deteriorate sharply tomorrow with nearly 8mm of rain; today may be the last viable window for several days.
Reasoning
Today's 1.2mm of rain breaks a three-day dry spell (April 28–30), leaving the dolerite surface likely damp at present, though the non-porous rock will not have absorbed moisture internally.
Moderate NW winds at 23 km/h and a warm high of 19.6°C should dry surface moisture within a few hours of rain ceasing, though the north-facing aspect offers no solar assistance.
Whin Sill dolerite does not weaken when wet, but loose blocks at the crag base remain a hazard — overnight temperatures have dropped below freezing several times in April, sustaining active freeze-thaw.
Early May is within the peregrine nesting restriction period; spring conditions are improving but the north aspect and 260m altitude keep temperatures cool and drying slower than lowland crags.
Contributing Factors
7
1.2mm of precipitation today means the rock surface is likely damp right now, though the small amount should clear quickly on non-porous dolerite.
Three consecutive dry days (April 28–30) with moderate winds and reasonable temperatures had allowed the crag to dry well before today's shower.
The north aspect receives no meaningful direct sun in spring, so damp patches and seepage lines dry by wind alone, significantly slower than south-facing crags.
The high Whin Sill ridge is very exposed, and today's 23 km/h NW wind will actively strip surface moisture from open faces within hours.
Dolerite absorbs negligible moisture, so the rock does not need extended internal drying — surface water is the only concern.
Tomorrow and the next two days bring heavy rain (7.9mm and 6.5mm) with humidity above 90%, meaning conditions are about to deteriorate significantly.
May is peak peregrine nesting season and Crag Lough is a known nesting site — some buttresses may be closed.
Recommendations
3
- If rain has stopped and the wind has been blowing for at least 2–3 hours, visually inspect the rock surface for dampness before climbing — dry dolerite will feel gritty and rough, damp rock will look dark and glossy.
- Check the BMC Regional Access Database for current peregrine nesting restrictions before travelling — some buttresses may be completely closed.
- Avoid routes with known seepage lines or sheltered recesses between buttresses, as these will remain damp longest on the north face.
Marginal — Assess Conditions
70%
9 days ago
The last measurable rain was 2.5mm on April 27, followed by two dry days with moderate easterly winds; the non-porous dolerite surface should be largely dry by now. However, overnight humidity was near 100% with full cloud cover, meaning condensation or residual dampness on this north-facing crag is likely — a visual check on arrival is essential before committing to climb.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Crag Lough is north-facing at 260m on the Whin Sill ridge, meaning it receives virtually no direct sun in April and overnight condensation can linger well into the morning.
- The prevailing easterly wind over recent days blows along the escarpment rather than directly onto the face, reducing its drying effectiveness on the north-facing cliff.
- Peregrine falcons nest at Crag Lough in spring — check BMC Regional Access Database (RAD) for current nesting restrictions before visiting, as sections may be closed.
- The crag base sits above Crag Lough (the lake), and seepage from the boggy plateau above can create localised wet patches on the rock even in otherwise dry conditions.
Warnings
2
- Peregrine falcons may be nesting — verify access status on BMC RAD before climbing.
- Dolerite is extremely slippery when damp; even a thin film of condensation can make holds treacherous.
Reasoning
Two full dry days since the last 2.5mm of rain on April 27 should be more than sufficient for non-porous dolerite to shed surface water, but very high overnight humidity (95–100%) and 100% cloud cover suggest condensation may currently coat the rock surface.
Moderate easterly winds (~15–17 km/h) have been blowing but are largely parallel to the north-facing aspect rather than impinging directly, limiting their drying effect; today's forecast of 22 km/h easterly with dropping humidity (76%) should improve surface conditions through the day.
Whin Sill dolerite does not suffer structural weakening when wet, but loose blocks at the crag base remain a hazard — overnight temperatures near freezing (3.4°C min) could contribute to minor freeze-thaw destabilisation of already-loose material.
Late April conditions are improving but the north-facing aspect at 260m means slow warming; overnight frost risk persists and days are still relatively cool, limiting evaporative drying.
Contributing Factors
6
No rain since 2.5mm on April 27, giving the non-porous dolerite ample time to shed surface water.
Humidity was 95–100% overnight with full cloud cover, making condensation on the cold north-facing rock very likely.
The north aspect receives almost no direct sunlight in April, so evaporative drying relies entirely on wind and ambient temperature.
Today's 22 km/h easterly wind with humidity dropping to 76% should help clear any residual surface moisture through the day.
Whin Sill dolerite does not absorb moisture, so surface water is the only concern and it dries within hours of rain stopping.
The 3.4°C minimum overnight means the rock will be cold and slow to warm, potentially holding condensation longer and posing minor freeze-thaw risk to loose blocks.
Recommendations
3
- Wait until mid-to-late morning before climbing to allow today's wind and warming temperatures to clear any overnight condensation from the rock surface.
- Physically touch and test the rock on arrival — dolerite becomes extremely slippery when even slightly damp, so abort if the surface feels greasy.
- Check the BMC RAD for current peregrine nesting restrictions at Crag Lough before your visit, as seasonal closures are common in spring.
Climbing Outlook