Condition Analysis
AI-powered assessment using site data and 14-day weather history
The last rain fell in the early hours of April 12th, giving roughly 30+ hours of drying by this afternoon, but the preceding weeks have been exceptionally wet (190mm in 28 days) and humidity remains high at 81%. The exposed aspect and moderate winds will have helped surface drying on this non-porous rhyolite, but seepage, residual dampness in cracks, and the NW aspect's poor sun exposure make on-site assessment essential.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect receives very limited direct sunlight in early April, meaning surface moisture lingers far longer than at south-facing venues in the Ogwen Valley.
- At 350m altitude the crag is frequently in cloud or mist, and the current 81% humidity suggests condensation may be wetting surfaces even without rain — check for a greasy film on the rock.
- The boulders here have excellent grit-like texture that provides superb friction when dry but becomes treacherously slippery with even a thin moisture film; test friction on lower problems before committing to anything committing.
- Heavy recent rainfall (33.8mm on April 11, 55mm in 7 days) can cause persistent seepage and drainage lines across certain boulders — inspect the backs and tops of boulders for water running down faces.
Warnings
2
- Rain is forecast for tomorrow (11.8mm on April 14), so today may be the only viable window this week — but do not let urgency override caution if the rock is damp on arrival.
- At 350m the crag may be in cloud today despite valley-level dryness; if visibility is poor or mist is settling on the rock, conditions are unsuitable.
Reasoning
7.7mm fell on April 12 (mostly before 07:00), followed by ~30 hours dry, but the NW aspect, 350m altitude, and 81% humidity mean surface moisture may not have fully cleared, particularly on sheltered or shaded faces.
Moderate westerly winds (18–33 km/h) and the exposed position will have assisted surface evaporation on the non-porous rhyolite, but the lack of direct sun on W/NW faces and persistent high humidity significantly slow drying.
Rhyolite is non-porous and does not suffer structural weakening when wet, so hold breakage and rock damage are not concerns here.
Early April in Snowdonia is a transitional period with short days, cool temperatures averaging 7°C, and frequent Atlantic fronts — the exceptionally wet preceding weeks (190mm in 28 days) point to saturated ground and elevated seepage risk.
Contributing Factors
7
54.8mm in the last 7 days including 33.8mm on April 11 and 7.7mm on April 12, with 190mm over 28 days indicating a prolonged saturated period.
No precipitation since early morning April 12 gives approximately 30+ hours of drying on non-porous rock, which is helpful but marginal given the conditions.
Humidity at 81% today with overnight readings reaching 87% significantly slows evaporation and risks condensation on cold rock surfaces.
Moderate SW winds at 18 km/h on an exposed site will aid surface drying on the volcanic rock.
The W/NW aspect receives minimal direct sunshine in early April, greatly reducing solar drying especially on the main boulder faces.
Rhyolite does not absorb water, so surface moisture is the only concern and drying times are shorter than for sandstone or gritstone.
The extremely wet preceding weeks mean the hillside is saturated, increasing the likelihood of water seeping across boulder surfaces from above.
Recommendations
3
- Visit in the afternoon when any residual surface moisture has had maximum drying time, and physically test friction on easy low problems before attempting anything harder.
- Avoid problems with known seepage lines, overhanging tops that collect drainage, or faces oriented directly NW where drying will be poorest.
- Bring a towel and consider postponing if you find a greasy film on the rock surface — friction loss on damp rhyolite is sudden and dangerous.
Previous Analyses
Do Not Climb
92%
2 days ago
Caseg Fraith is currently wet and unsuitable for climbing. Heavy rain yesterday (33.8mm on April 11) followed by further rain today (6.8mm) means the rock will be saturated with surface water; the recent weeks have been exceptionally wet with over 200mm in the last 28 days, leaving 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 very little direct sunshine, especially in spring, so surface moisture lingers far longer than at south-facing crags in the Ogwen Valley.
- At 350m altitude, the crag is frequently enveloped in low cloud and hill fog during unsettled spells, which prevents evaporation even when it isn't actively raining.
- The exposed position on the high pass means strong SW/W winds are common and do help strip surface moisture, but persistent high humidity (79–94% recently) negates much of this drying effect.
- Despite rhyolite being non-porous, the grit-like textured boulders at Caseg Fraith have numerous micro-features that trap water droplets, and the lichen-covered landings and approach can be treacherous when wet.
Warnings
2
- Active rain today on already saturated ground makes the boulders, landings, and approach extremely slippery — serious fall and injury risk.
- The A5 roadside location can create a false sense of easy access, but wet rhyolite at Caseg Fraith is treacherously slick and bouldering falls onto wet ground are dangerous.
Reasoning
The rock is almost certainly wet today: 33.8mm fell yesterday, 6.8mm is falling today, and there have been zero consecutive dry days — surface water and seepage will be widespread across the boulders.
Despite the exposed position and moderate winds (~32 km/h SW), the NW-facing aspect at 350m receives negligible direct sun in April, humidity remains above 80%, and there has been no meaningful dry window to allow evaporation since the heavy rain began on April 9.
Rhyolite does not suffer structural damage when wet, so hold breakage and rock conservation are not concerns here — the issue is purely friction and safety.
Early April in Snowdonia is peak unsettled season with frequent Atlantic fronts; the 201.5mm over 28 days is typical of a very wet spring spell, and overnight temperatures near freezing at 350m mean slow evaporation rates.
Contributing Factors
7
33.8mm fell yesterday and 6.8mm today, with 54.1mm in the last 7 days — the rock will be thoroughly wet with active surface water.
There has been no dry window since the rain resumed on April 9, giving the rock no opportunity to shed moisture.
The W/NW facing aspect receives very limited direct sunlight in April, significantly slowing any surface drying that wind alone cannot achieve.
At 350m in active weather, the crag is likely in or near cloud base, maintaining saturated conditions even between showers.
Strong winds (32+ km/h) at the exposed high pass do assist surface drying when rain stops, and would accelerate recovery during any dry window.
Average humidity of 79% over the last week, with several days above 90%, severely limits evaporative drying potential.
Rhyolite does not absorb water, meaning once rain stops and conditions improve, the surface can dry relatively quickly compared to sandstone.
Recommendations
3
- Do not visit today — the rock is wet and conditions are unsafe for bouldering on friction-dependent rhyolite.
- Monitor conditions from April 17 onward, when a potential dry window with moderate winds may allow the rock to dry sufficiently for an assess-on-arrival visit.
- If visiting the Ogwen Valley during this spell, consider low-level south-facing alternatives that dry faster, or indoor climbing.
Do Not Climb
92%
3 days ago
Caseg Fraith is currently receiving heavy rain today (23.7mm) on top of a very wet recent period (39mm in the last 7 days, 185mm in the last 28 days). The rock will be thoroughly wet and extremely slippery — conditions are clearly unsuitable for climbing today.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect means it faces directly into the prevailing SW/W winds that have been driving rain onto the rock face repeatedly over the past month, maximising surface wetting.
- At 350m altitude on the Ogwen pass, the crag is frequently in low cloud during unsettled spells like this, meaning ambient moisture and mist can keep surfaces damp even between rain showers.
- The renowned grit-like texture of this rhyolite provides outstanding friction when dry but becomes treacherously slippery when wet — the rough surface gives a false sense of security.
- Roadside access near the A5 makes it easy to drive up and do a quick visual check on drier days, but seepage from the hillside above can persist for days after heavy rain at this exposed venue.
Warnings
2
- Active heavy rain and saturated rock make bouldering extremely dangerous today — falls on wet rhyolite at Caseg Fraith are a serious injury risk.
- The forecast shows continued unsettled weather with rain on most days through April 15; do not assume a brief dry spell means the rock is ready.
Reasoning
With 23.7mm falling today and 39mm in the past week on top of an extremely wet month (185mm), the rock surface and surrounding ground are thoroughly saturated.
Despite strong winds (40 km/h SW today), active heavy rain means no drying is occurring; the W/NW aspect faces directly into the rain-bearing wind, and the exposed position offers no shelter.
Rhyolite is non-porous and does not suffer structural damage when wet, so hold breakage is not a concern — the risk is entirely friction-related and safety-related.
Early April at 350m in Snowdonia is a marginal season with low temperatures (averaging 7.4°C), high humidity, and frequent Atlantic weather systems; extended dry windows are rare and drying is slow.
Contributing Factors
7
23.7mm of precipitation today makes the rock actively wet and completely unsuitable for friction-dependent climbing.
39mm in the last 7 days and 185mm in the last 28 days mean the ground and any seepage sources are fully saturated, prolonging drying times.
There has been no dry spell to allow any drying — the last truly dry window (April 6–8) was immediately followed by further rain.
Winds of 40 km/h would normally aid drying, but during active rain they are driving moisture directly onto the W/NW-facing rock.
Humidity at 86% and 350m altitude means the crag is likely in or near low cloud, suppressing any evaporation.
Max temperature of only 5.9°C today severely limits evaporative drying potential.
Rhyolite does not absorb water, so once rain stops and wind dries the surface, recovery can be relatively quick given the right conditions.
Recommendations
3
- Do not visit today — the rock is actively wet and dangerous for bouldering on friction-dependent rhyolite.
- Monitor conditions after April 12; if a genuine 24–36 hour dry window opens with wind and lower humidity, a visit with on-site assessment could be worthwhile.
- When conditions improve, drive up to the A5 layby and do a hands-on check of the rock surface before committing — seepage from above can persist after rain at this venue.
Do Not Climb
70%
4 days ago
Caseg Fraith has had almost no meaningful dry spell recently — 10.9mm fell on April 9th and a further 0.9mm today, with 179mm in the last 28 days. Despite the exposed position and non-porous rock type, the combination of persistent dampness, high humidity, and zero consecutive dry days means surfaces are very likely still wet or greasy, and conditions are not suitable for climbing today.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith sits at 350m on an exposed pass and is frequently in cloud during unsettled spells — at this altitude, orographic enhancement means actual precipitation is likely higher than valley-floor readings suggest.
- The W/NW aspect means direct sunlight is limited to late afternoon and evening only, significantly reducing solar drying, especially in early spring when the sun angle is still low.
- The roadside boulders near the A5 vary in exposure — some sheltered blocks beneath Tryfan's flanks can harbour seepage and remain damp long after open faces have dried.
- The grit-like texture of Caseg Fraith rhyolite provides exceptional friction when dry but becomes treacherous when damp, as the rough surface can give a false sense of security before suddenly losing grip.
Warnings
2
- Wet rhyolite at Caseg Fraith can be deceptively slippery — the textured surface may feel grippy but can give way without warning, risking falls onto bouldering mats or rocky ground.
- Heavy rain is forecast for tomorrow (20.9mm) which will completely reset any drying progress made today.
Reasoning
With 10.9mm on April 9th, 0.9mm today, and zero consecutive dry days, the rock surfaces are almost certainly still carrying moisture — seepage lines and sheltered faces will be wet.
Although the site is wind-exposed (25 km/h SW today) which aids evaporation, the W/NW aspect receives very little direct sun in early April, and humidity at 76% is too high to drive rapid drying in the few hours since the last rain.
Rhyolite does not suffer structural weakening when wet — there is no risk of hold breakage or rock damage from climbing on damp surfaces.
Early April in Snowdonia at 350m is a volatile period: temperatures are modest (averaging 7.8°C over the past week), days are still relatively short, and the frequency of Atlantic fronts keeps the rock persistently damp between brief dry windows.
Contributing Factors
7
10.9mm fell yesterday and 0.9mm today, with 25mm in the last 7 days and a very wet 179mm over 28 days — the site has barely had a chance to dry.
There have been no consecutive fully dry days leading into today, meaning any drying that occurred was repeatedly interrupted by further precipitation.
Average humidity over the past week is 79% and today sits at 76%, which significantly slows evaporation from rock surfaces at altitude.
The exposed position with 25 km/h SW winds today helps strip surface moisture, partially compensating for the lack of sun on the NW aspect.
Rhyolite does not absorb water internally, so once surface moisture evaporates the rock will be climbable — but surface water is still present.
The W/NW-facing boulders receive minimal direct sun until late afternoon in early April, reducing the most effective drying mechanism.
At 350m on the Ogwen pass, the crag is frequently enveloped in low cloud during unsettled weather, which adds condensation rather than allowing drying.
Recommendations
3
- Wait for at least one full dry day with low humidity before visiting — the forecast suggests April 14th may offer the first genuine window.
- If you do visit, carry a towel and test friction carefully on low-level problems before committing to anything elevated or committing.
- Check the BMC RAD for any seasonal bird nesting restrictions at Caseg Fraith and nearby Ogwen Valley crags before your visit.
Do Not Climb
35%
5 days ago
Caseg Fraith is likely damp today: 1.8mm of rain has fallen today on top of a very wet recent period (216mm in 28 days, 32mm in the last 7 days), humidity is high at 85%, and overnight humidity reached 98% suggesting condensation and mist at altitude. Although rhyolite dries relatively quickly on its surface, the NW-facing aspect at 350m with persistent cloud cover limits drying, and the famous grit-like texture that gives superb dry friction becomes treacherous when damp.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's roadside boulders near the A5 at Ogwen sit in a notoriously damp microclimate where cloud often lingers on the pass, and overnight humidity reaching 98% strongly suggests the rock is condensation-wet this morning.
- The W/NW aspect means these boulders receive very little direct sun — especially in early April — so even after a dry spell, residual seepage and condensation can persist on north-facing surfaces well into the day.
- The exposed position does aid wind-drying when winds are strong, and today's 32km/h westerly will help strip surface moisture, but the current rain (1.8mm) and high humidity counteract this.
- The volcanic rock here has an unusually rough, grit-like texture that provides exceptional friction when dry but becomes deceptively greasy when damp — a thin film of moisture can make moves feel dramatically harder and more dangerous than expected.
Warnings
2
- The rock is almost certainly wet or condensation-damp right now — bouldering on damp rhyolite at Caseg Fraith poses a serious slip and fall risk.
- Bird nesting restrictions may apply at nearby crags in the Ogwen Valley from February to June — check BMC RAD before visiting any cliff venues in the area.
Reasoning
The rock is very likely damp: today has seen 1.8mm of rain, overnight humidity peaked at 98% suggesting condensation on the boulders, and the preceding days included significant rainfall (11.3mm on Apr 4, 6.9mm on Apr 2, 16.8mm on Apr 3) with only a brief two-day dry window on Apr 7–8.
Yesterday (Apr 8) was warm and dry with temps up to 18.9°C and low 54% humidity — excellent drying — but the NW-facing aspect at 350m means limited direct sun, and overnight conditions completely reversed with humidity rising to 98% and cloud cover at 100%, likely re-wetting surfaces through condensation before today's rain arrived.
Rhyolite is non-porous and does not suffer structural damage when wet; the risk is entirely about friction loss and climber safety on damp surfaces.
Early April in the Ogwen Valley is transitional with short drying windows, frequent Atlantic fronts, and the sun angle is still too low to effectively dry NW-facing rock at 350m — conditions typically don't become reliable here until late May.
Contributing Factors
7
1.8mm of rain today combined with 85% humidity means the rock surface is currently wet or at minimum very damp.
Humidity reached 98% overnight with 100% cloud cover, strongly suggesting condensation formed on the cold rock surfaces before today's rain even began.
216mm over 28 days and 32mm in the last 7 days means the surrounding ground and any seepage paths are thoroughly saturated, contributing to ambient moisture.
Two dry days with warm temperatures (up to 18.9°C) and low humidity on Apr 7 would have dried exposed surfaces effectively before conditions deteriorated again overnight.
31.7km/h W winds on this exposed site will actively strip surface moisture once rain stops, potentially drying the rock within hours if precipitation ceases.
At 350m facing W/NW, Caseg Fraith receives minimal direct spring sunshine and is frequently enveloped in cloud, significantly slowing the drying process.
Rhyolite does not absorb water, so once surface moisture evaporates the rock can offer full friction — no extended internal drying period is needed.
Recommendations
3
- Wait for a sustained dry spell of at least 24 hours with low humidity before visiting — the rock needs time to fully dry after today's rain and the saturated conditions of recent weeks.
- If you do visit later today, test friction carefully on low, safe holds before committing to any problems — the grit-like texture can feel deceptively grippy on first touch but fail under load when damp.
- Check the forecast for April 10 which looks more promising with only 0.4mm and dropping humidity to 70%, though verify conditions on arrival.
Marginal — Assess Conditions
55%
8 days ago
After a very wet spell culminating in rain on April 4th–5th, today is the first fully dry day with warming temperatures and a southerly breeze — but only one dry day following 1.8mm yesterday and 241mm over the past month means residual surface moisture in seepage zones and sheltered faces is likely. The rhyolite should be drying well on exposed surfaces, but verification 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 the southerly wind today offers limited direct drying on the main faces; sheltered boulders facing north-west will retain moisture longest.
- The roadside boulders near the A5 at lower elevation may dry faster than higher problems on the hillside, so conditions can vary significantly across the venue.
- At 350m in the Ogwen Valley, cloud can roll in rapidly and re-wet surfaces even on nominally dry days — monitor conditions throughout a session.
- The grit-like texture of the rhyolite here provides outstanding friction when fully dry but can feel deceptively grippy while still subtly damp, leading to unexpected slips on steeper problems.
Warnings
2
- Overnight humidity was high (88–89%) and may have deposited condensation on rock surfaces — allow time for this to burn off before climbing.
- The extremely wet March/April means seepage and ground-level dampness will persist around boulder bases even if top surfaces feel dry.
Reasoning
The last significant rain was 11.3mm on April 4th and 1.8mm on April 5th, with only one full dry day since; surface moisture is likely clearing on exposed faces but seepage lines and sheltered NW-facing rock will still be damp.
Today's southerly wind at 17 km/h and warmth (13.4°C max) will aid drying, but the W/NW aspect means the main faces are somewhat sheltered from this wind direction, slowing evaporation compared to a westerly blow.
Rhyolite is non-porous and not at risk of structural damage from moisture — the concern here is purely friction loss and climber safety on damp surfaces.
Early April in Snowdonia at 350m means short effective drying windows, high background humidity (87% average this week), and the possibility of overnight frost or condensation re-wetting surfaces.
Contributing Factors
7
241mm in the last 28 days and 40mm in the last 7 days indicate a saturated local environment with abundant residual ground moisture.
Only one consecutive dry day after rain on April 4th–5th is marginal drying time, especially at 350m altitude with high ambient humidity.
A jump to 13.4°C with 75% humidity and light southerly wind is the best drying day in over a week, promoting surface evaporation on exposed rock.
Today's southerly wind doesn't directly hit the main NW-facing bouldering surfaces, reducing the wind-drying effect on the most popular problems.
At 350m with 87% average humidity over the past week, ambient moisture keeps the rock environment damp and slows drying significantly.
The volcanic rock does not absorb water, so surface moisture can evaporate relatively quickly once conditions improve — no deep saturation concern.
The exposed high-pass position generally promotes quick surface drying when wind aligns with the aspect, and yesterday's strong westerlies (38 km/h) will have helped.
Recommendations
3
- Visit in the afternoon when the day's warmth has had maximum drying effect, and test friction carefully on lower problems before committing to anything committing.
- Focus on south- or west-facing boulders that caught yesterday's strong westerly wind and today's sun — avoid shaded NW-facing problems that will be last to dry.
- Bring a towel and be prepared to walk away if surfaces feel greasy; conditions may vary dramatically between individual boulders across the venue.
Do Not Climb
30%
9 days ago
Caseg Fraith has received 2.8mm of rain today on top of a very wet week (41.9mm in 7 days) and an exceptionally wet month (242.2mm in 28 days). Despite strong westerly winds aiding surface drying, the rock is almost certainly still damp and conditions are not suitable for climbing today.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect means the persistent SW/W winds of recent weeks have been driving rain directly onto the rock faces, maximising wetting.
- At 350m altitude in the Ogwen Valley, the crag is frequently in cloud during unsettled spells — ambient moisture and mist can keep surfaces damp even between rain events.
- The bouldering here relies heavily on the exceptional friction of the grit-like rhyolite texture, which is dramatically reduced when even slightly damp, making marginal conditions particularly hazardous on slab and friction-dependent problems.
- Seepage and drainage from the surrounding hillside above the boulders can persist for days after heavy rain, keeping certain landings boggy and lower sections of boulders wet.
Warnings
2
- Wet rhyolite at Caseg Fraith is extremely slippery despite its normally superb friction — do not be lured into climbing because the rock 'looks' dry on the surface.
- Strong winds (38+ km/h) today and in the coming days pose a direct safety risk for highball bouldering and exposed positions at this altitude.
Reasoning
With 2.8mm of rain today, 11.3mm yesterday, and 16.8mm the day before, plus no consecutive dry days, the rock surfaces are almost certainly wet or at best damp.
Strong westerly winds (38 km/h today) on this exposed site will promote rapid surface evaporation, but the W/NW aspect means these winds have been driving rain directly onto the rock, and the lack of any meaningful dry spell means drying has not had a chance to take effect.
Rhyolite is non-porous and does not suffer structural damage when wet — there is no risk of hold breakage or rock conservation concerns from climbing in these conditions.
Early April in the Ogwen Valley at 350m is still firmly in the transitional spring season — low sun angle provides minimal direct warming on the NW-facing rock, temperatures are cool (average 6.7°C), and the persistent Atlantic weather pattern shows no sign of a sustained dry spell.
Contributing Factors
7
2.8mm today with 11.3mm yesterday and 16.8mm the day before means the rock has had no opportunity to dry.
242.2mm in 28 days indicates a persistently saturated environment with waterlogged ground and prolonged seepage.
There has not been a single fully dry day leading into today, preventing any meaningful drying cycle.
38 km/h winds on this exposed crag will help strip surface moisture relatively quickly once rain stops.
87% average humidity over the past week significantly slows evaporation and keeps rock surfaces damp.
Average 6.7°C over the past week at 350m provides little thermal energy for drying, and the NW aspect receives minimal direct sun.
The dominant SW/W wind direction has been driving rain directly onto these W/NW-facing boulders for weeks.
Recommendations
3
- Do not climb at Caseg Fraith today — the rock is almost certainly damp and friction will be severely compromised.
- Monitor conditions for April 7th, which shows 0mm forecast rain and warmer temperatures (15.7°C) with lower humidity (66%) — this could be the first viable window.
- If visiting the Ogwen Valley regardless, consider walking approaches or checking conditions in person but be prepared to walk away if the rock feels greasy.
Do Not Climb
90%
10 days ago
Caseg Fraith is currently wet and unsuitable for climbing. Today has seen 6.7mm of rain on top of a very wet preceding week (50.9mm in 7 days), with high humidity (91%) and zero consecutive dry days — the rock will be thoroughly wet and slippery despite strong winds.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect means it faces directly into the prevailing SW/W winds that have driven almost continuous rain over the past month, maximising surface wetting.
- At 350m altitude on the Ogwen pass, the crag is frequently enveloped in low cloud and orographic precipitation that may not register fully in weather station data, meaning actual moisture levels could be worse than reported.
- The bouldering here relies heavily on the exceptional friction of dry rhyolite — even a thin film of moisture on these problems dramatically reduces grip on the slab and friction-dependent moves that define many of the classic problems.
- Seepage and drainage from the hillside above can keep the base of some boulders and lower landings boggy for days after heavy rain, affecting both climbing and landing zones.
Warnings
3
- Rock will be extremely slippery today — rhyolite loses its renowned friction almost entirely when wet, creating a serious fall risk on boulder problems.
- Landings and approach ground will be waterlogged and potentially treacherous after weeks of heavy rain; take extra care with crash pad placement.
- Winds of 44+ km/h on exposed boulders at 350m pose an additional safety hazard, particularly on highballs and exposed top-outs.
Reasoning
The rock is certainly wet today: 6.7mm of rain is falling on a crag that has received over 50mm in the past week and 235mm in the past 28 days, with zero consecutive dry days and 91% humidity.
Despite strong W/SW winds (44.6 km/h today) that would normally aid drying on this exposed site, the continuous rainfall and very high humidity mean evaporation is negligible and no meaningful drying has occurred.
Rhyolite is non-porous and not at risk of structural damage from moisture, so the concern is entirely about friction loss and climber safety on wet, slippery surfaces.
Early April in Snowdonia at 350m is firmly within the wet spring season; low sun angle and NW aspect mean minimal solar heating to assist drying, and temperatures averaging 7°C further slow evaporation.
Contributing Factors
7
6.7mm of precipitation today means the rock is actively wet right now, making friction-dependent climbing dangerous.
Over 50mm in the past 7 days and 235mm in 28 days indicates a thoroughly waterlogged environment with saturated ground and persistent surface runoff.
There have been zero consecutive dry days leading into today, so no drying window has occurred since the last significant rainfall.
Average humidity of 89% over the past week with 91% today severely inhibits evaporation even with wind exposure.
Winds of 44.6 km/h today and sustained strong winds throughout the week do aid surface drying, but are insufficient to overcome continuous rain and near-saturated air.
The W/NW facing aspect receives very limited direct sunlight in early April, reducing solar-assisted drying significantly at this time of year.
At 350m in the Ogwen Valley, the crag is frequently at or near cloud base during unsettled weather, keeping surfaces damp even between showers.
Recommendations
3
- Do not climb today — the rock is wet and dangerously slippery; wait for the dry spell forecast from April 6th onwards.
- Target April 7th or later as the first realistic window, when two consecutive dry days with lower humidity and warmer temperatures should allow meaningful surface drying.
- On arrival after any dry spell, perform a thorough touch-test on multiple holds and especially friction-dependent faces before committing to problems — seepage and sheltered areas may retain moisture longer than expected.
Do Not Climb
92%
11 days ago
Caseg Fraith is currently receiving heavy rain today (20.7mm) on top of a very wet recent period (nearly 250mm in 28 days), making conditions clearly unsuitable. The rock will be saturated with surface water and extremely slippery despite its excellent dry-condition friction properties.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect means it is fully exposed to the prevailing SW/W weather systems that have been delivering persistent rain over the past month, and the boulders will be directly wind-lashed and rain-soaked.
- At 350m altitude in the Ogwen Valley, the crag is frequently in cloud during wet spells, meaning condensation and mist can keep surfaces damp even between rain showers.
- The grit-like texture of the rhyolite here provides outstanding friction when dry but becomes treacherously slippery when wet — the rough surface gives a false sense of security that can catch climbers out.
- Roadside access near the A5 means conditions can be quickly checked on arrival, but seepage from the hillside above can persist for days after heavy rain, particularly on lower boulders.
Warnings
3
- Active heavy rain today makes all rock surfaces dangerously slippery — do not attempt to climb.
- The prolonged wet period means hillside seepage and drainage channels may be running across boulders even where they appear sheltered.
- Strong gusty winds (35+ km/h) at this exposed 350m crag create additional safety risks for highball problems and exposed approaches.
Reasoning
With 20.7mm falling today, 48.9mm in the past 7 days, and zero consecutive dry days, the rock surface is actively wet and will have standing water in features and on slab faces.
Despite the exposed position and strong SW winds (35.6 km/h today), active rainfall means no drying is occurring; the W/NW aspect receives minimal direct spring sun, further hindering any drying once rain stops.
Rhyolite is non-porous and does not suffer structural damage when wet, so hold breakage and rock conservation are not concerns here.
Early April at 350m altitude in Snowdonia means short days, low sun angle, cool temperatures (~7°C average), and the tail end of the wettest season — conditions are slow to improve and the ground remains saturated.
Contributing Factors
7
20.7mm of rain today means the rock is actively wet with no possibility of dry climbing conditions.
Nearly 250mm of rain in the past 28 days has left the surrounding ground and drainage lines fully saturated, prolonging seepage onto boulders.
There has been no dry spell to allow any surface drying, with rain recorded on every recent day.
Humidity at 92% today and averaging 87% over the past week means even sheltered surfaces will retain a film of moisture.
Strong SW winds at 35.6 km/h on an exposed site will assist rapid surface drying once rain ceases, but this benefit is irrelevant while it is actively raining.
Rhyolite does not absorb water so will dry relatively quickly from the surface once conditions allow, and there is no risk of structural damage.
The W/NW facing boulders receive minimal direct sun in early April, particularly in the morning, slowing surface evaporation.
Recommendations
3
- Do not climb today — the rock is actively wet and extremely slippery; wait for a sustained dry spell.
- Monitor the forecast for April 6th, which shows zero precipitation and dropping humidity — this could be the first realistic window if April 5th stays light.
- When you do visit, check the lower boulders near the road for hillside seepage which can persist long after rain stops at this saturated time of year.
Do Not Climb
35%
12 days ago
The rock at Caseg Fraith is very likely still damp today following 2.9mm of rain yesterday evening and 1.1mm forecast today, set against an extremely wet recent period (235mm in 28 days). Although rhyolite dries relatively quickly in good conditions, persistent high humidity (86% average over the last week), cloud cover, and the NW aspect at 350m mean surface moisture is unlikely to have cleared — we recommend not climbing today.
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 in early spring, meaning overnight condensation and residual moisture linger well into the afternoon.
- The boulders sit on an exposed high pass near the A5 and can be enveloped in low cloud, which at this altitude frequently deposits moisture directly onto the rock even without recorded rainfall.
- The famous grit-like texture of Caseg Fraith rhyolite provides outstanding friction when dry but becomes deceptively greasy when damp — a thin moisture film on the micro-crystals dramatically reduces grip.
- Seepage and drainage from the saturated hillside above can keep the base of many problems and lower landings boggy for days after heavy rain, affecting both rock conditions and landing zones.
Warnings
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- Damp rhyolite at Caseg Fraith can be deceptively slippery — the micro-crystal texture that gives superb dry friction becomes very greasy with even a thin moisture film, increasing the risk of unexpected slips on highball problems.
- Saturated ground and boggy landings from weeks of heavy rain may make crash pad placement difficult and reduce their effectiveness.
Reasoning
With 2.9mm of rain last evening (mostly between 18:00–20:00), 1.1mm forecast today, and ambient humidity consistently above 83%, the rock surface is almost certainly still carrying moisture.
Although moderate westerly winds (~24 km/h) help evaporate surface water, the NW aspect receives negligible direct sun in early April and the persistent cloud cover (near 100% overnight) likely deposited additional condensation, negating any wind-driven drying.
Rhyolite is non-porous and structurally unaffected by moisture — there is no risk of hold breakage or rock damage from climbing when damp, though friction loss makes climbing hazardous.
Early spring at 350m in Snowdonia means short days, low sun angles that barely reach NW-facing rock, frequent cloud immersion, and saturated ground from an exceptionally wet March — conditions are slow to improve at this time of year.
Contributing Factors
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235mm over 28 days with 37mm in the last 7 days alone indicates a thoroughly saturated local environment with persistent runoff and ground moisture.
2.9mm fell between 18:00 and 20:00 yesterday, wetting the rock surface with insufficient drying time overnight given high humidity and cloud.
1.1mm is forecast for today, meaning any drying progress will likely be reversed.
Humidity has averaged 86% over the past week and remained above 88% overnight, strongly inhibiting evaporation and promoting condensation on cold rock.
The W/NW-facing rock at 350m receives very little direct solar radiation in early April, especially with persistent cloud cover above 80%.
Winds around 24 km/h from the west on an exposed site do assist surface drying, though this is partially offset by high humidity.
Rhyolite does not absorb water so only surface moisture needs to evaporate, meaning drying can be rapid once conditions improve.
There have been zero consecutive fully dry days leading into today, confirming the rock has had no sustained drying window.
Recommendations
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- Wait for a sustained dry spell — ideally two or more consecutive dry days with humidity below 75% — before visiting Caseg Fraith.
- If you travel to the Ogwen Valley, consider lower-altitude sheltered crags with a southerly aspect where conditions may be marginally better.
- Check the BMC RAD for any early-season bird nesting restrictions in the Ogwen area before planning a visit.
Climbing Outlook