Condition Analysis
AI-powered assessment using site data and 14-day weather history
Recent days have seen repeated light precipitation and persistently high humidity, with today bringing further showers through the afternoon; the rock is unlikely to be reliably dry. Tomorrow brings 11.6mm of rain, and the five-day outlook shows continued unsettled weather with no meaningful dry window.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect means it receives minimal direct sun, so surface moisture from light showers and mist lingers far longer than at sunnier Ogwen crags.
- At 350m altitude the crag is frequently enveloped in low cloud, which deposits moisture on the rock even without measurable rainfall — humidity above 80% at this elevation often means the rock is damp to the touch.
- The renowned grit-like texture of the rhyolite provides outstanding friction when dry but becomes treacherously slippery when damp, making bouldering especially risky as falls are unroped.
- Roadside access from the A5 means a quick retreat is easy — worth driving up to check conditions visually, but be prepared to walk away.
Warnings
2
- Bouldering on damp rhyolite is a serious slip hazard — the rock becomes very slippery when wet and falls are unroped.
- Near-freezing overnight temperatures on May 10–11 may produce verglas on the rock surface at this altitude; check early-morning conditions carefully.
Reasoning
Light but frequent precipitation over the past week (14.2mm in 7 days spread across multiple days), combined with 1.8mm today including afternoon showers, means the rock surface is almost certainly damp right now.
The NW aspect, 350m altitude, persistent cloud cover (near 100% for most of today), and humidity around 80% severely limit evaporative drying — even the moderate wind is insufficient to fully dry surfaces between showers.
Rhyolite is non-porous and structurally unaffected by moisture; the only risk is friction loss on the slippery wet surface, which is significant for unroped bouldering.
Early May in Snowdonia at altitude remains cool and damp; overnight temps near freezing at the weekend (forecasts of -1.7°C and -2.5°C) introduce potential frost/verglas risk on the rock surface.
Contributing Factors
6
Today has scattered showers (1.8mm total) with rain at 08:00, 13:00–15:00 and 17:00–18:00, keeping rock surfaces intermittently wet.
Seven-day average humidity of 82% at 350m altitude means the rock rarely dries fully, even between rain events.
The W/NW-facing aspect receives very little direct sun, dramatically slowing surface evaporation compared to south-facing crags.
The exposed position with 16.6 km/h SW winds today provides some drying effect on surface moisture during dry spells.
Tomorrow's forecast of 11.6mm will thoroughly wet the crag and reset any drying progress.
Forecasts of -1.7°C (May 10) and -2.5°C (May 11) at altitude create a risk of ice or verglas on the rock surface early in the day.
Recommendations
3
- Do not climb today — afternoon showers are forecast and the rock is unlikely to be dry enough for safe bouldering.
- Monitor the forecast for a sustained dry spell of at least 2–3 days with lower humidity before visiting; no such window appears in the next five days.
- If you are in the area, consider lower-altitude or south-facing alternatives in the Ogwen Valley that dry more quickly.
Previous Analyses
Do Not Climb
40%
2 days ago
Light rain is falling today and the rock has had no meaningful dry spell since showers on May 3rd; with high humidity, cloud cover, and further rain forecast from the afternoon onward, surface moisture is very likely present. Conditions are unsuitable for climbing today and deteriorate sharply from May 9th.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect means it receives very little direct sun, so any surface moisture lingers far longer than at south-facing Ogwen crags.
- At 350m altitude the crag is frequently in cloud — today's near-100% cloud cover and 80%+ humidity suggest condensation may be wetting the rock even between rain events.
- The renowned grit-like texture of the rhyolite here offers superb friction when dry but becomes treacherously slippery when damp; even a thin film of moisture dramatically reduces grip on the rounded volcanic holds.
- Roadside access near the A5 makes it easy to drive up, do a touch-test on the rock, and retreat if conditions are poor — worth doing before committing on marginal days.
Warnings
2
- Rhyolite at Caseg Fraith becomes very slippery when damp — a thin moisture film may not be visually obvious but will dramatically reduce friction on the textured holds.
- Heavy rain is forecast for May 9–10 (35mm+); do not plan climbing at this venue for the end of the week.
Reasoning
Light showers on May 1–3 (10.3mm total) were followed by only a trace-dry day on May 4, another 0.3mm on May 5, and 1.4mm today, meaning the rock has not had a sustained dry period and surface moisture is almost certainly present.
With a W/NW aspect receiving minimal direct sun, persistent cloud cover near 100%, humidity averaging 77–85%, and only moderate easterly winds today (~12 km/h) that do not blow directly onto this aspect, drying has been very slow and insufficient.
Rhyolite is non-porous and structurally sound when wet; the risk here is purely friction loss on damp surfaces, not hold breakage.
Early May in Snowdonia at 350m remains cool and damp; spring conditions are improving but the recent unsettled spell with frequent fronts is typical, and overnight temperatures near 5°C with high humidity promote condensation.
Contributing Factors
6
Showers on May 1–3 totalling 10.3mm, plus trace amounts on May 5 and 1.4mm today, mean the rock has had no sustained dry window.
Humidity has averaged 77–85% over the past week with near-total cloud cover today, suppressing evaporation and promoting condensation at altitude.
The W/NW-facing rock receives very little direct sunlight, meaning any moisture present dries far more slowly than at south-facing venues.
Light showers of 0.6–0.3mm are forecast from 14:00–19:00, wetting any surfaces that may have started to dry during the morning.
The exposed position at 350m means wind does help remove surface moisture, but today's ~12 km/h easterly is modest and not directed onto the W/NW face.
The volcanic rock does not absorb water, so once genuinely dry conditions arrive the surface will be climbable relatively quickly.
Recommendations
3
- Wait for a sustained dry spell — the rock needs at least one full dry day with wind or sun before conditions will be reliable here.
- If visiting tomorrow (May 7), do a thorough touch-test on multiple holds before climbing; the morning may offer a brief window if overnight rain stays minimal.
- Consider south-facing crags in the Ogwen Valley instead, which will dry significantly faster in current conditions.
Marginal — Assess Conditions
72%
3 days ago
Caseg Fraith has had two consecutive dry days following light rain on May 3rd (4.4mm), and the exposed, wind-swept position should have cleared most surface moisture from the non-porous rhyolite. However, the NW aspect at 350m, persistent cloud cover, and moderate humidity mean some sheltered or shaded surfaces could still hold dampness — a visual check on arrival is advised.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect at 350m receives very little direct sun, so drying relies heavily on wind and ambient conditions rather than solar heating — sheltered boulder faces and north-facing landings may retain moisture longest.
- The boulders here are renowned for their grit-like textured rhyolite which provides outstanding friction when dry but can feel deceptively greasy when even lightly damp, particularly on the slabby problems.
- At 350m on the Ogwen high pass, the crag is frequently in low cloud or mist even when valleys are clear — check conditions at crag level, not from the A5 roadside.
- The recent prolonged wet spell (110mm over 28 days) means ground conditions around boulder landings will be saturated and boggy, affecting pad placement and approach comfort.
Warnings
2
- Cloud immersion at 350m can deposit significant condensation moisture even without rainfall — if you arrive in mist or low cloud, conditions are likely too damp for safe friction-dependent climbing.
- The saturated ground and boggy landings increase the risk of slipping on descents and poor pad placement; take extra care with spotter positioning.
Reasoning
The last significant rain was 4.4mm on May 3rd, with two full dry days since; surface moisture on the non-porous rhyolite should have largely evaporated, though sheltered NW-facing surfaces at this altitude may retain dampness given the persistent cloud and moderate humidity (77% today).
Moderate northerly winds (13–14 km/h) on the exposed pass have aided drying over the last two days, but the NW aspect means virtually no direct solar heating to assist evaporation, leaving wind as the primary drying mechanism.
Rhyolite is non-porous and extremely hard — there is no risk of structural damage or hold breakage from moisture; the concern is purely friction loss on damp surfaces.
Early May in Snowdonia at 350m means temperatures remain cool (5–10°C), drying is slower than summer, and cloud immersion at crag level is common; daylight hours are good but effective drying hours are limited by aspect.
Contributing Factors
7
No meaningful precipitation since 4.4mm on May 3rd, giving the non-porous rock two full days to shed surface water.
The high pass location with 13–14 km/h winds today provides good air circulation that assists surface drying even without direct sun.
The W/NW aspect at this time of year receives very limited direct sunlight, significantly slowing evaporation on sheltered faces compared to south-facing crags.
At 350m in the Ogwen Valley, the crag is frequently immersed in cloud which can deposit condensation moisture even on rain-free days.
Humidity of 77% today (dropping to 64–65% in the afternoon) is moderate but not ideal, limiting the atmosphere's capacity to absorb surface moisture.
110mm of rain over the past 28 days means the ground is thoroughly saturated, and seepage from surrounding hillside may keep some boulder bases damp.
Cloud cover drops significantly from mid-afternoon (46% at 16:00, 0% at 19:00) with humidity falling to 64%, suggesting the best friction window is late afternoon.
Recommendations
3
- Aim for the late afternoon window (15:00–19:00) when cloud cover and humidity are forecast to be at their lowest, maximising friction on the textured rhyolite.
- Perform a thorough touch-test on multiple boulder faces on arrival — if any feel cool and clammy or show damp patches in sheltered areas, wait or move to better-drying problems.
- Bring extra crash pads and be prepared for boggy, saturated landings around the boulders after the prolonged wet spell.
Marginal — Assess Conditions
65%
4 days ago
Yesterday saw 4.4mm of rain in very humid, overcast conditions, and today has been dry but with high humidity and persistent cloud cover through the morning. By early afternoon humidity is dropping into the low 70s with moderate wind, so exposed surfaces should be drying, but the NW aspect and 350m altitude mean residual dampness is plausible — a visual check on arrival is essential.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect receives very little direct sun in spring, so drying relies heavily on wind and ambient conditions rather than solar heating.
- The crag sits at 350m on an exposed pass near the A5, meaning orographic cloud and hill fog can deposit moisture even without recorded rainfall — today's morning cloud cover at 80–99% at altitude may have contributed condensation.
- The rough grit-like texture of the rhyolite here provides exceptional friction when dry but can hold fine surface moisture in its micro-texture, making it feel deceptively grippy before being truly dry.
- The preceding week (May 1–3) deposited ~10mm of rain with sustained high humidity (82–91%), and ground-level seepage from surrounding boggy terrain can keep the base of some boulders damp longer than the weather suggests.
Warnings
2
- Residual dampness on NW-facing surfaces may not be visually obvious but can dramatically reduce friction on steeper problems — test carefully before committing to highballs.
- Hill fog or low cloud at 350m is possible despite the forecast; if visibility drops or the rock feels cold and clammy, conditions have deteriorated and you should stop.
Reasoning
4.4mm fell yesterday in near-saturated conditions (91% humidity, 100% cloud), and while today is dry, morning humidity remained above 85% until mid-morning, so some surface dampness likely persists on sheltered and NW-facing surfaces.
The NE wind today (13–14 km/h) does not directly strike the W/NW-facing rock, limiting wind-assisted drying, though the exposed hilltop position provides some air movement; by afternoon humidity drops to ~71% which should allow exposed surfaces to dry.
Rhyolite is non-porous and does not suffer structural damage when wet — there is no hold-breakage risk from climbing on damp rock.
Early May at 350m in Snowdonia is transitional; days are lengthening but the NW aspect still gets minimal direct sun, and overnight temperatures dropping to 6°C slow evaporation considerably.
Contributing Factors
7
4.4mm fell yesterday with 91% average humidity, and the preceding three days totalled ~10mm, keeping surfaces saturated until very recently.
Today is forecast completely dry with zero precipitation and humidity dropping from 95% overnight to 71% by mid-afternoon.
The W/NW-facing rock receives minimal direct sun in spring, so drying is slower than at south-facing crags and depends primarily on wind and ambient conditions.
The crag's exposed hilltop location ensures reasonable air circulation even when the NE wind doesn't directly hit the face.
Rhyolite does not absorb water, so surface moisture is all that needs to evaporate — there is no deep-seated dampness risk.
At 350m with 80–95% cloud cover through the morning, orographic mist may have deposited additional moisture not captured by precipitation gauges.
Cloud cover is forecast to drop dramatically from 85% at 3pm to near 0% by 7pm, with humidity falling to 71%, creating a good late-afternoon drying window.
Recommendations
3
- Wait until early-to-mid afternoon (after 1pm) to allow maximum drying time, and carefully touch-test holds before committing to problems.
- Focus on the most wind-exposed and least sheltered boulders first, as these will have dried fastest; avoid any problems in sheltered hollows or near boggy ground.
- Bring a towel or chalk rag to test and dry individual holds — the rough micro-texture can trap fine surface moisture that reduces friction below safe levels.
Do Not Climb
60%
4 days ago
Caseg Fraith received 4.4mm of rain today with 90% humidity and light NE winds, following several days of intermittent rain (nearly 10mm over the past three days). The rock is almost certainly wet or damp right now, and with the NW/W aspect sheltered from the current NE wind, drying will be slow despite the exposed altitude.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect means the current NE airflow provides limited direct drying effect on the main rock faces, as wind is largely hitting the back of the crag.
- At 350m in the Ogwen Valley, the crag is frequently in low cloud during periods of high humidity (90% today), which can deposit additional moisture even without recorded rainfall.
- The famous grit-like texture of the rhyolite here provides superb friction when dry but the rough surface can hold thin films of moisture in micro-pockets, making it deceptively slippery before it looks fully wet.
- Roadside access near the A5 makes it easy to drive up and do a quick visual/touch check of conditions without committing to a long approach.
Warnings
2
- Rhyolite at Caseg Fraith becomes extremely slippery when wet — the grit-like texture that gives superb dry friction offers almost no grip when damp, creating a serious fall risk on bouldering problems.
- At 350m altitude the crag can be enveloped in cloud even when the valley below appears clear — always reassess conditions on arrival.
Reasoning
With 4.4mm of rain today on top of 5.9mm over the preceding two days, and humidity at 90%, the rock surface is almost certainly wet or at least substantially damp right now.
The NE wind at ~12 km/h offers minimal drying benefit to the W/NW-facing rock, and the high humidity will severely retard evaporation — meaningful drying is unlikely before tomorrow at the earliest.
Rhyolite is non-porous and not structurally vulnerable to moisture, so there is no risk of hold breakage or route damage from climbing on damp rock.
Early May in Snowdonia brings unpredictable weather with moderate temperatures (~12°C) that are adequate for drying but insufficient to rapidly clear moisture at 350m altitude, especially with persistently high humidity.
Contributing Factors
6
Active rainfall today means the rock surface is currently wet and will need a full drying window before conditions improve.
Humidity at 90% dramatically slows surface evaporation, keeping rock damp even after rain stops.
The prevailing NE wind hits the back of the W/NW-facing crag, providing minimal airflow across the climbing surfaces.
Nearly 10mm over the past three days means seepage and ground moisture are elevated, contributing to a damp environment around the boulders.
The volcanic rock does not absorb water, so once surface moisture evaporates the rock will be ready to climb without an extended drying period.
While exposure generally aids drying, at 350m the crag is more prone to cloud cover and cooler temperatures that offset the wind-drying benefit.
Recommendations
3
- Do not climb today — the rock is wet from today's rain and conditions are not suitable for safe friction-dependent climbing.
- Tomorrow (May 4th) is forecast dry with moderate NE winds; drive up and do a touch-test on the rock before committing, as drying may be slow on the NW-facing surfaces.
- The best window this week looks to be May 8th–9th, with two consecutive dry days, lower humidity, and SE winds that will help dry the W/NW-facing rock.
Do Not Climb
45%
4 days ago
Caseg Fraith received 4.7mm of rain today and has had over 10mm in the last three days, with high humidity (87%) and light NE winds offering limited drying on this W/NW-facing crag. The rock is almost certainly still wet or damp on the surface, and the renowned friction that makes this venue worthwhile will be significantly compromised.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect means the current NE winds blow across or away from the face, providing poor direct airflow for drying the climbing surfaces.
- The crag sits at 350m on an exposed pass where cloud and mist can linger even when valleys are clear, maintaining surface moisture well beyond what lowland weather stations suggest.
- The grit-like texture of the rhyolite here provides exceptional friction when dry but can feel deceptively grippy when damp — thin moisture films on the micro-crystals reduce friction dramatically without obvious visual wetness.
- Roadside access near the A5 makes it easy to drive up, do a touch-test on the rock, and retreat without commitment if conditions are poor.
Warnings
2
- Today's rain means the rock is very likely still wet — rhyolite becomes dangerously slippery when damp despite its normally excellent friction.
- Cloud base may sit at or below 350m in current conditions, maintaining persistent dampness even if rain has stopped.
Reasoning
With 4.7mm of rain today, 2.8mm yesterday, and 3.1mm the day before, the rock surface is very likely still wet or retaining a damp film, especially on the sheltered NW-facing aspects.
Light NE winds at ~12 km/h provide minimal drying benefit on this W/NW-facing crag, and the high humidity of 87% severely limits evaporation rates at 350m altitude.
Rhyolite is non-porous and does not suffer structural damage when wet — there is no hold breakage or rock degradation concern here.
Early May in North Wales at 350m means temperatures are still modest (8–13°C) and cloud base frequently sits at or below crag level, prolonging dampness and reducing effective drying hours.
Contributing Factors
6
4.7mm today following 2.8mm and 3.1mm on the previous two days means the rock has had no opportunity to fully dry.
Humidity at 87% today severely inhibits surface evaporation, keeping any residual moisture on the rock.
NE winds blow across or away from the W/NW-facing rock, providing minimal direct airflow to aid surface drying.
Winds at only 11.9 km/h are modest for this normally exposed site and insufficient to force rapid surface drying.
Rhyolite does not absorb water so once rain stops and conditions improve, surface moisture can clear relatively quickly.
Temperatures around 8–13°C are neither warm enough to drive fast evaporation nor cold enough to create freeze-thaw concerns.
Recommendations
3
- Wait at least until tomorrow (May 4th) which is forecast dry, and check conditions on arrival — the rock may still need additional hours to dry given high humidity.
- If you do visit, perform a thorough touch-test on multiple surfaces before committing to any problems, paying particular attention to NW-facing and sheltered areas.
- Consider lower-altitude alternatives in the Ogwen Valley that may have better aspect for the NE winds and faster drying times.
Do Not Climb
40%
4 days ago
Caseg Fraith has received 4.2mm of rain today with high humidity (86%) and light winds, following several days of intermittent rainfall. Although the rock is non-porous and had a good dry spell in late April, the recent return to wet weather means surfaces are likely damp and greasy — we recommend waiting for a dry day with better drying conditions.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect means it receives very little direct sun, especially in the morning, so surface moisture from today's rain will linger well into the afternoon and evening.
- At 350m altitude on the Ogwen pass, the crag is frequently enveloped in low cloud and mist even when lower valleys are dry, which can deposit persistent surface moisture invisible in forecasts.
- The renowned grit-like texture of the rhyolite here provides exceptional friction when dry but becomes notably treacherous when damp — the rough surface gives a false sense of security before friction suddenly fails.
- Seepage from the hillside above can persist for days after prolonged wet spells; the heavy mid-April rainfall (over 80mm in a week) may still be feeding seepage lines on some bloc faces.
Warnings
2
- Rock surfaces are wet today — rhyolite becomes very slippery when damp and falls on bouldering landings can cause serious injury.
- High-altitude mist and cloud may persist even if lower areas appear dry; do not assume conditions based on what you see from the A5.
Reasoning
With 4.2mm of rain today, 2.8mm and 3.1mm on the preceding two days, and humidity at 86%, rock surfaces are almost certainly wet or at least damp across most of the bouldering area.
Light NE winds at 10.4 km/h offer minimal drying assistance, and the W/NW aspect means the crag is sheltered from the prevailing wind direction today, further slowing evaporation of today's rainfall.
Rhyolite is non-porous and does not suffer structural weakening when wet, so hold breakage and rock damage are not concerns here.
Early May in Snowdonia is transitional — days are lengthening and temperatures are mild, but high-altitude crags remain prone to cloud cover, mist, and lingering dampness between frontal systems.
Contributing Factors
7
Active precipitation today means rock surfaces are currently wet, and light winds with high humidity will slow drying considerably.
Rainfall on May 1st (2.8mm), 2nd (3.1mm), and today (4.2mm) totalling over 10mm means there has been no opportunity for surfaces to fully dry.
Humidity near saturation severely inhibits evaporation, meaning even surfaces not directly rained on may be damp from condensation.
Wind at only 10.4 km/h from the NE provides poor drying for this W/NW-facing crag, as the rock face is sheltered from the incoming airflow.
Rhyolite does not absorb water, so once rain stops and conditions improve, surface moisture can clear relatively quickly.
A sustained dry spell from April 21–30 allowed deep drainage and ground drying, meaning subsurface seepage should be less of an issue than after the heavy mid-April rains.
At 350m in the Ogwen Valley, the crag is prone to being enveloped in low cloud and orographic drizzle that weather stations may underreport.
Recommendations
3
- Wait at least one full dry day with lower humidity before visiting — tomorrow (May 4th) is forecast dry but with 86% humidity, so assess carefully if you go.
- If you visit in the coming days, test friction on low-level easy problems first and be prepared to walk away if the rock feels greasy or polished.
- Check BMC RAD for any active bird nesting restrictions at Caseg Fraith, as peregrine and raven nesting season is well underway in May.
Marginal — Assess Conditions
55%
5 days ago
After an extended dry spell from April 20–30, light rain returned on May 1 (2.8mm) and today (2.3mm), breaking the dry streak. The rock had been thoroughly dried out during the preceding 9+ dry days, and the recent rain is light, but today's precipitation and high humidity (83%) mean surfaces may still be damp — a visual check on arrival is essential.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect means it receives minimal direct sun, especially in the morning, so light rain from today may linger on shaded faces into the afternoon.
- The crag's exposed position on the Ogwen pass means wind will assist surface drying, but today's moderate SW wind (14 km/h) is not strong enough to clear moisture rapidly at this aspect.
- The famous grit-like texture of the rhyolite here provides exceptional friction when dry but can become deceptively greasy with even a thin film of moisture — test friction carefully before committing to problems.
- At 350m altitude, cloud and mist are common in the Ogwen Valley during unsettled spells, and today's high humidity (83%) suggests low cloud may be sitting on the crag, preventing effective drying.
Warnings
2
- Today's rain means some surfaces will be slippery — rhyolite friction drops dramatically with even a thin moisture film, creating a genuine fall risk on slabs and friction-dependent moves.
- Cloud may be sitting on the crag at 350m given today's humidity; if you arrive to mist or drizzle, do not climb.
Reasoning
Today's 2.3mm of rain on top of yesterday's 2.8mm means surfaces are likely wet or at least damp right now, despite the excellent drying period that preceded it.
The W/NW aspect and moderate 14 km/h SW wind provide only limited drying assistance; the rock had been bone-dry before May 1, so internal seepage is not a concern, but surface moisture from today's rain needs wind and time to clear.
Rhyolite is non-porous and extremely hard — there is no structural risk from these conditions; the concern is purely friction and safety.
Early May in Snowdonia is still unpredictable; temperatures are mild (~13°C) but humidity is elevated, and the forecast suggests continued unsettled conditions with high humidity through the coming week.
Contributing Factors
7
2.3mm of precipitation today means rock surfaces are likely wet or damp at the time of assessment.
2.8mm fell on May 1 after a 9-day dry period, reintroducing surface moisture to previously well-dried rock.
Nine consecutive dry days (April 21–30) with low humidity and easterly winds thoroughly dried the rock, so there is no deep seepage or residual moisture from the earlier wet April.
83% humidity with SW airflow at 350m altitude suggests possible low cloud and slow evaporation of surface moisture.
The north-west facing aspect receives very little direct sunlight, slowing the drying of today's rain.
The crag's exposed position on the pass means wind assists drying, though today's 14 km/h is only moderate.
Rhyolite does not absorb water, so once surface moisture evaporates the rock will be fully dry — no extended internal drying needed.
Recommendations
3
- Visit later in the day to allow the morning's rain to clear, and perform a thorough touch-test on holds before committing to any problems.
- Prioritise south- or east-facing boulders and overhanging problems where rain may not have wetted the climbing surface.
- If surfaces feel at all greasy or damp, wait — conditions should improve significantly if tomorrow's forecast 0.5mm stays light and is followed by drier days.
Marginal — Assess Conditions
55%
6 days ago
After an excellent dry spell from April 20–30, today's 3.2mm rain has broken the run and introduced fresh surface moisture. The rock had been thoroughly dry before today, so provided the rain has stopped and the exposed aspect allows wind-drying, conditions may be acceptable — but on-ground verification is essential given the NW-facing aspect and high humidity.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect means it receives very little direct sun, especially in spring mornings — any moisture from today's rain will rely almost entirely on wind evaporation rather than solar drying.
- The crag's exposed position on the Ogwen pass means moderate SW winds today (13 km/h) will help strip surface moisture from the rhyolite, but this is relatively light for this venue.
- The famous grit-like texture of the rhyolite here provides outstanding friction when dry but becomes notably slippery when even slightly damp — subtle residual moisture can be deceptive on this rock.
- Seepage can persist at the base of some problems and in cracks after rain, even when the main faces appear dry; check holds individually before committing to problems.
Warnings
2
- Today's rain means surface conditions are uncertain — do not assume the rock is dry; test friction carefully before climbing.
- The forecast shows no reliable dry window in the next 5 days; conditions are likely to remain marginal or deteriorate through the week.
Reasoning
Today's 3.2mm of rain on previously bone-dry rhyolite means surface moisture is present, though the rock's non-porous nature means water sits on the surface and does not penetrate — the question is whether it has had time to evaporate by the time of climbing.
The W/NW aspect receives minimal direct sun, so drying depends on the moderate 13 km/h SW wind and ambient conditions; with 74% humidity and only partial exposure to wind from this direction, full surface drying may take several hours after rain ceases.
No structural risk — rhyolite is non-porous volcanic rock that does not weaken when wet; the concern is purely friction loss on damp surfaces.
Early May in Snowdonia is transitional — days are lengthening and temperatures are reasonable (~14.5°C today), but the forecast shows an unsettled and cooling trend with near-daily light rain through the coming week.
Contributing Factors
7
3.2mm of rain today has deposited fresh surface moisture on the rock, ending a 10-day dry spell.
Ten consecutive dry days (April 20–30) with low humidity and easterly winds left the rock thoroughly dried out before today's rain.
Rhyolite does not absorb water, so today's light rain sits on the surface and can evaporate relatively quickly in favourable conditions.
The W/NW-facing aspect receives very little direct sun in spring, making wind the primary drying mechanism.
The exposed position at 350m catches wind well, and today's 13 km/h SW breeze will assist surface drying despite being lighter than typical for this site.
Humidity at 74% slows evaporation compared to the recent dry spell when it dropped below 50%.
Light rain is forecast on each of the next four days (0.7–4.3mm), with rising humidity and cooling temperatures, preventing a sustained dry-out.
Recommendations
3
- Visit later in the day to allow maximum wind-drying time after today's rain, and physically test friction on lower holds before attempting anything committing.
- Carry a towel and soft brush, and be prepared to walk away if the rock feels greasy — even slight dampness on this rhyolite dramatically reduces friction.
- Consider waiting for the next sustained dry window; the coming week looks persistently unsettled with daily light rain and high humidity.
Likely Safe to Climb
88%
9 days ago
Caseg Fraith has had three consecutive dry days following an extended dry spell since April 20, with only a trace of rain (0.1mm) in the last week. Today's low humidity (57%), warm temperatures, and brisk easterly wind should ensure excellent friction on the rough rhyolite — conditions look genuinely good for climbing.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The W/NW-facing aspect means the prevailing easterly wind today blows across or slightly onto the crag, providing good airflow for drying but offering little direct sun — however, the extended dry spell makes this largely irrelevant.
- At 350m altitude, overnight humidity was high (82–94%) and cloud cover was near 100% yesterday morning, so condensation or mist dampness on the rock surface overnight is possible — check holds feel dry before committing.
- Caseg Fraith's grit-like rhyolite texture provides outstanding friction when dry but can feel deceptively greasy if there is any residual condensation or lichen moisture — test friction on a low problem first.
- The roadside location near the A5 makes it easy to drive up, assess conditions quickly, and retreat if any localised seepage or dampness is found on specific boulders.
Warnings
1
- Check the BMC Regional Access Database (RAD) for any active bird nesting restrictions at Caseg Fraith — peregrine and raven nesting season runs February to June in the Ogwen Valley.
Reasoning
With only 0.1mm of rain in the past 7 days and the last significant rainfall (3.0mm) on April 20, surface moisture from precipitation should be entirely gone from this non-porous rhyolite.
Three full dry days with moderate easterly winds (13–28 km/h) and dropping humidity have provided ample drying time for any residual surface moisture, though the W/NW aspect receives limited direct sun to burn off overnight condensation.
Rhyolite is non-porous and does not suffer structural weakening when wet — there is no hold breakage or rock damage concern at this venue.
Late April in Snowdonia is transitional; daytime temperatures are reasonable (10–18°C) but overnight lows can still approach freezing, and mountain mist or cloud immersion at 350m can deposit surface moisture even without rainfall.
Contributing Factors
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Only 0.1mm of precipitation in the last 7 days, with the last meaningful rain (3.0mm) falling on April 20 — nine days ago.
Today's humidity of 57% with a brisk 28 km/h easterly wind will keep surfaces dry and promote evaporation of any overnight condensation.
Yesterday's humidity reached 93–94% overnight at altitude with near-total cloud cover, meaning condensation or mist dampness may have formed on rock surfaces overnight.
Today's forecast high of 15.6°C is well above freezing and warm enough to aid rapid evaporation of any residual surface moisture.
Rhyolite does not absorb water, so the only concern is surface moisture which evaporates quickly in current conditions.
The crag receives limited direct sunlight due to its aspect, but the extended dry spell and wind exposure compensate adequately.
Recommendations
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- Arrive mid-morning or later to allow any overnight condensation to evaporate in the wind and warming temperatures.
- Test friction on a low, easy problem before committing to anything committing — the grit-like texture should feel positively grippy if conditions are right.
- Bring a soft brush to clean any lichen or grit from holds, and remove all tick marks after your session.
Climbing Outlook