Condition Analysis
AI-powered assessment using site data and 14-day weather history
Caseg Fraith is currently saturated after a prolonged wet spell — nearly 160mm over the last 28 days with significant rain today (7.1mm) and no meaningful dry window ahead. The rock will be wet and slippery, and the entire five-day forecast shows continued rainfall with high humidity, making dry conditions extremely unlikely.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- At 350m on an exposed NW/W-facing aspect near Tryfan, Caseg Fraith sits in cloud frequently during prolonged wet spells, meaning humidity at the crag can be even higher than valley-floor readings suggest.
- The boulders here rely heavily on the exceptional friction of dry rhyolite — even a thin film of moisture dramatically reduces grip on the otherwise rough, grit-like texture.
- Roadside access near the A5 means conditions can be checked quickly without a long approach, but the exposed position means wind-driven rain wets all aspects of the boulders thoroughly.
- Seepage and residual dampness can linger in sheltered hollows and on downhill faces of boulders even after the exposed tops have dried.
Warnings
2
- Wet rhyolite boulders are extremely slippery — falls from even modest heights onto rocky landings carry serious injury risk.
- At 350m the crag may be in cloud with near-zero visibility during this weather pattern; do not approach in poor visibility if unfamiliar with the area.
Reasoning
The rock is almost certainly wet right now: 7.1mm of rain today on top of 37mm in the last week and 160mm in the last 28 days, with humidity at 96–100% throughout the day.
Despite the exposed position and moderate winds, there has been no meaningful dry window — the last two fully dry days were June 13–14, but 0.9mm fell on the 15th and heavy rain resumed today, so any drying was immediately undone.
Rhyolite is non-porous and not at risk of structural damage from moisture, but the slipperiness hazard on wet volcanic rock at this altitude is severe for bouldering.
Early summer in Snowdonia can bring prolonged Atlantic frontal systems, and the current pattern of persistent SW winds and rain is typical; conditions should eventually improve but the forecast offers no respite for at least five days.
Contributing Factors
5
Nearly 160mm over 28 days with 37mm in the last week alone means the entire site is thoroughly wet.
7.1mm today with humidity at 96–100% and 100% cloud cover ensures the rock remains saturated on the surface.
Every day in the five-day forecast shows rain (3–19mm) with humidity above 89%, preventing any meaningful drying.
The exposed W/NW position would aid drying in a dry spell, but currently channels wind-driven rain directly onto the boulders.
Rhyolite will not suffer structural damage and will dry relatively quickly once rain stops and humidity drops.
Recommendations
3
- Do not visit Caseg Fraith this week — conditions are persistently wet with no dry window in the forecast.
- Monitor conditions from around June 22 onward, when the forecast shows a potential dry day; two consecutive dry days with dropping humidity would be needed before the boulders offer reliable friction.
- If in the Ogwen Valley area, consider checking lower-altitude sheltered crags or indoor walls instead.
Previous Analyses
Marginal — Assess Conditions
55%
2 days ago
After a prolonged wet spell (over 150mm in the last 28 days), three dry days and today's dry window have allowed the exposed rhyolite surfaces to shed standing water, but persistent cloud cover, high humidity, and the NW aspect mean residual dampness in sheltered spots is likely. Conditions this afternoon look the best window, but climbers should check holds carefully before committing.
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, so even after dry spells, shaded faces and north-facing boulders can retain surface moisture longer than expected.
- At 350m in the Ogwen Valley, low cloud and mist frequently envelop the boulders — today's 100% cloud cover all day means no solar drying assistance.
- The rough grit-like texture of the rhyolite here provides exceptional friction when dry but can become treacherously greasy when even slightly damp, especially on slab problems.
- Seepage from the saturated hillside above (after 150mm+ of recent rain) can create wet patches on lower boulders and at the base of certain problems that persist well beyond surface drying.
Warnings
2
- Heavy rain (18.5mm) is forecast for tomorrow — today is likely the only climbing window for several days.
- Ground-level seepage from the saturated hillside may affect landing zones and lower boulder faces even where upper surfaces appear dry.
Reasoning
The rock surface has had three full dry days plus today, but 23.7mm fell on June 11 and over 100mm fell in the preceding ten days, so while the non-porous rhyolite surface itself sheds water quickly, ground seepage and ambient humidity (83% average last week) will keep sheltered areas damp.
Moderate winds (22–37 km/h) through the exposed site have aided evaporation of surface water, but the W/NW aspect and persistent 100% cloud cover today severely limit solar drying, leaving the effective drying rate well below what three dry days would achieve at a sunny, low-altitude crag.
Rhyolite is non-porous and does not suffer structural weakening when wet — hold breakage and rock damage are not concerns here.
Mid-June should offer reasonable drying conditions, but this has been an exceptionally wet period; the saturated ground and high water table at 350m mean hillside seepage onto boulders is a real factor even during dry spells.
Contributing Factors
6
No significant rain since June 12 (0.2mm trace), giving exposed surfaces time to dry.
Over 150mm in 28 days with repeated heavy falls means the hillside is saturated, increasing seepage risk onto boulders.
Humidity averaging 83% over the last week and forecast at 63–86% today limits evaporative drying and risks condensation on cool rock.
100% cloud cover throughout today eliminates solar heating that would otherwise accelerate surface drying on the already shaded NW-facing boulders.
Moderate winds of 12–15 km/h today help strip surface moisture from exposed boulder faces.
18.5mm forecast for June 16 will re-wet all surfaces, making today's afternoon the only realistic window before another extended damp period.
Recommendations
3
- Target the afternoon window (roughly 12:00–18:00) when humidity drops to 63–68% and temperatures peak, giving the best chance of dry surfaces.
- Visually and physically check every boulder face before climbing — rub the rock with your palm and avoid any problem that feels even slightly greasy.
- Prioritise steep, overhanging problems and those on the most wind-exposed faces; avoid slabs and north-facing walls where residual dampness is most likely.
Marginal — Assess Conditions
55%
3 days ago
After a prolonged wet spell depositing nearly 58mm in the last 7 days and over 150mm in the last 28 days, the rock has had only two dry days to recover. The exposed, windy aspect and non-porous rhyolite should allow surface moisture to clear relatively quickly, but persistent high humidity (83% average) and the NW-facing aspect at 350m will have slowed drying — seepage and sheltered damp patches are likely.
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, meaning evaporative drying relies heavily on wind rather than solar heating — critical after the recent prolonged wet period.
- At 350m in the Ogwen Valley, the crag is frequently in low cloud or hill fog even in summer, which can re-wet surfaces and maintain high humidity even on nominally dry days.
- The bouldering here is low-level and roadside near the A5, making it easy to do a quick visual and touch assessment before committing — take advantage of this.
- Despite being volcanic, the BVS rhyolite here has an unusually rough grit-like texture that performs exceptionally in dry conditions but can feel deceptively grippy when slightly damp — test friction carefully on easier moves first.
Warnings
2
- Significant seepage is possible after 150mm of rain in the last month — wet landing zones and damp holds can appear suddenly even on otherwise dry-looking boulders.
- The forecast turns wetter from June 17 onwards; conditions are unlikely to improve beyond the next two days.
Reasoning
Two dry days following a very wet fortnight (57.8mm in 7 days, 23.7mm just three days ago on June 11) means exposed surfaces should be largely dry but seepage lines, sheltered overhangs, and north-facing facets are likely still damp.
Strong westerly winds (28–37 km/h) on June 12–13 combined with today's dry, calmer conditions will have stripped surface moisture from exposed faces, but the consistently high humidity (78–83%) limits full drying, especially in sheltered spots.
Rhyolite is non-porous and does not suffer structural weakening when wet — there is no risk of hold breakage from moisture.
Early June at 350m in Snowdonia means long daylight hours aid drying, but the recent weather pattern has been persistently unsettled with above-average rainfall, and temperatures have been cool for the season (averaging only 11°C).
Contributing Factors
7
Nearly 58mm fell in the last 7 days alone, with heavy events on June 8 (23.6mm) and June 11 (23.7mm), saturating the ground and creating extensive runoff and seepage.
June 13 and today (June 14) have been dry with moderate wind, allowing exposed surfaces to begin drying.
Average humidity of 83% over the last week significantly slows evaporation and can maintain a damp film on shaded rock surfaces.
Strong winds (up to 37 km/h on June 12) across the exposed site accelerate surface drying on open faces despite the high humidity.
The W/NW-facing aspect receives limited direct sunlight, reducing solar-driven evaporation and prolonging damp conditions in sheltered spots.
Rhyolite does not absorb water, so only surface moisture and seepage need to clear — no internal drying time required.
Average temperatures of only 11°C over the past week are well below summer norms, reducing evaporation rates.
Recommendations
3
- Visit and visually inspect the rock before climbing — test friction on easy terrain first, as the gritty texture can feel deceptively grippy when slightly damp.
- Prioritise the most exposed, wind-facing boulders which will have dried fastest; avoid sheltered alcoves and north-facing problems where seepage is likely to linger.
- If the rock feels greasy or damp patches are visible, wait — the forecast suggests another unsettled spell arriving from June 17, so today and tomorrow may offer the best window.
Do Not Climb
35%
4 days ago
Despite today being nominally dry, Caseg Fraith has endured a prolonged period of heavy rainfall (nearly 70mm in the last 7 days alone) with extremely high humidity, and the NW-facing aspect at 350m means drying has been minimal. With only one dry day behind us and persistent high humidity, the rock is very likely still wet or damp in many areas.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The W/NW aspect receives very little direct sun, meaning surface moisture lingers far longer than at south-facing Ogwen crags — even after a nominally dry day the rock can remain damp.
- At 350m altitude on the Ogwen pass, the crag is frequently enveloped in low cloud and hill fog, which can deposit moisture independently of recorded rainfall.
- Seepage lines and drainage channels are common on the BVS rock here and will still be actively weeping after the sustained wet spell of the past two weeks.
- The exposed position means strong westerly winds can assist drying but also drive horizontal rain and mist directly onto the climbing faces.
Warnings
2
- Rhyolite becomes extremely slippery when wet — the textured surface that gives superb dry friction offers almost no grip when damp, creating a serious fall risk on bouldering problems.
- Cloud base frequently drops below 350m in current conditions, depositing moisture on the rock even when no rain is forecast at valley level.
Reasoning
With 69mm of rain in the last 7 days, 23.7mm just two days ago, and only one full dry day since, surface moisture is almost certainly still present across much of the crag, compounded by 81–94% humidity throughout the period.
Although the exposed position and today's 27 km/h westerly wind aid evaporation, the NW aspect receives negligible direct sun and the consistently high humidity (81% today) severely limits evaporative drying — one dry day is insufficient after such a prolonged wet spell.
Rhyolite is non-porous and not at risk of structural damage from moisture, so hold breakage is not a concern.
Early June in Snowdonia often brings persistent Atlantic fronts, and current conditions reflect an unusually wet and cool spell; temperatures averaging only 11°C over the last week further slow drying at altitude.
Contributing Factors
7
Nearly 70mm fell in the last 7 days with significant events on June 8 (23.6mm) and June 11 (23.7mm), saturating the crag environment.
Just a single day without meaningful precipitation is far too little drying time for a shaded, high-altitude NW-facing crag after two weeks of sustained rain.
Humidity has averaged 86% over the past week and remains at 81% today, severely inhibiting surface evaporation.
The W/NW facing rock receives minimal direct sunlight, especially on lower sections, meaning solar drying is negligible even on clear days.
Strong westerly winds (27+ km/h today) promote airflow across the rock surface, providing the main drying mechanism at this site.
The volcanic rock does not absorb water internally, so once surface moisture evaporates the rock returns to full friction quickly.
The forecast shows rain returning from June 16 (3.1mm) through June 18 (8.5mm), limiting the available drying window to at most two days.
Recommendations
3
- Wait for at least one more full dry day with lower humidity before visiting — June 15 looks the most promising window if it stays dry.
- If you do visit, test friction carefully on lower problems first and be prepared to walk away if the rock feels greasy or slick.
- Check UKClimbing and local Ogwen forums for up-to-date condition reports before making the journey, as seepage patterns here vary significantly.
Do Not Climb
35%
5 days ago
Caseg Fraith has been battered by an extended wet spell — over 75mm in the last 7 days and 150mm in the last 28 days — with heavy rain as recently as yesterday (23.7mm on June 11). Despite today's strong westerly winds aiding surface drying, the rock is very likely still wet or damp in sheltered spots, and high humidity (84%) is inhibiting evaporation. We recommend waiting for at least one full dry day with good wind before climbing.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect means it catches the prevailing SW/W winds directly, which accelerates surface drying but also means the crag bears the brunt of rain-bearing Atlantic weather systems.
- At 350m altitude in the Ogwen Valley, the crag is frequently enveloped in low cloud and orographic mist even when valleys below appear dry — actual conditions may be wetter than weather station data suggests.
- The bouldering here relies on the exceptional friction of the grit-textured rhyolite; even a thin film of residual moisture dramatically reduces grip on the slabby and friction-dependent problems.
- Seepage and drainage from the hillside above can keep certain boulder bases and lower faces damp for extended periods after prolonged wet spells like this one.
Warnings
2
- Rhyolite becomes dangerously slippery when wet — friction-dependent boulder problems that feel trivial when dry can cause serious falls on damp rock.
- At 350m, orographic cloud may wet the rock even when no rain is forecast; be prepared to abort if mist rolls in.
Reasoning
With 23.7mm falling yesterday, 5.1mm on June 9, 5.2mm on June 10, and persistent humidity above 80%, the rock surface is almost certainly still carrying moisture in sheltered areas and seepage zones despite today's strong winds.
Today's 37 km/h westerly wind hitting this exposed W/NW crag will strip surface moisture from fully exposed faces rapidly, but only 0.5–1 dry day has elapsed since the last significant rain, which is insufficient for comprehensive drying given the saturated ground and high humidity.
Rhyolite is non-porous and not at risk of structural damage from moisture; the concern is purely friction loss on wet surfaces.
Early June conditions in Snowdonia are often unsettled, and the current pattern of repeated Atlantic fronts with brief dry interludes is typical; at 350m, temperatures averaging only 11°C slow evaporation compared to lowland crags.
Contributing Factors
6
Over 76mm in the last 7 days across multiple rain events, with 23.7mm as recently as yesterday, has thoroughly saturated the ground and rock surfaces.
Average humidity of 87% over the past week and 84% today severely slows evaporation and can cause condensation on cold rock at altitude.
Today's 37 km/h W wind directly hitting this W/NW-facing crag will accelerate surface drying on exposed faces.
Only today (with 0.3mm trace rain) separates the crag from yesterday's heavy 23.7mm downpour — far too short for reliable drying at this altitude and humidity.
The W/NW aspect receives limited direct sunlight, particularly on lower and shaded boulder faces, reducing solar-assisted evaporation.
Four consecutive dry days are forecast from June 13–16, which should progressively improve conditions.
Recommendations
3
- Wait until at least June 14 to allow two full dry days with wind exposure before visiting — June 15 with warmer temperatures and southerly airflow would be ideal.
- If visiting before then, carry a towel and check friction on easy low problems first; abandon the session if holds feel greasy or polished.
- Avoid seepage-prone and north-facing boulder faces for several days longer, as these will retain moisture well after exposed faces have dried.
Do Not Climb
95%
6 days ago
Caseg Fraith is currently saturated after nearly 85mm of rain in the past 7 days, with heavy rain continuing throughout today (28.7mm forecast). The rock will be thoroughly wet and slippery, with no drying window available today or in the immediate forecast.
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 winds that have been driving persistent rain onto the rock face for over a week.
- At 350m altitude in the Ogwen Valley, the crag is likely sitting in cloud today (100% cloud cover, 95–99% humidity), meaning even surfaces sheltered from direct rain will be condensation-wet.
- The rough grit-like texture of the rhyolite here, while superb when dry, can feel deceptively grippy when damp — but friction drops dramatically on fully wet surfaces, making the bouldering landing zones slippery too.
- Roadside access near the A5 makes it easy to drive past and visually check conditions without committing, which is advisable over the coming days as the crag dries.
Warnings
3
- The rock is dangerously slippery today with active heavy rain and near-100% humidity at altitude.
- Bouldering landing zones will be waterlogged and slippery — increased risk of injury on descent or from falls.
- The crag is likely in low cloud; poor visibility adds further risk on the exposed hillside.
Reasoning
The rock is thoroughly wet — 84.9mm fell in the last 7 days with 28.7mm today alone, and humidity has been above 80% for over a week, preventing any meaningful drying.
Despite the exposed position and strong W/SW winds (25–37 km/h), persistent rain and near-100% humidity mean wind is not providing any net drying effect; the W/NW aspect receives no useful direct sun to aid evaporation.
Rhyolite is non-porous so there is no structural or hold-breakage risk from the saturation, but surface friction is critically compromised.
Early June should offer improving conditions, but this has been an exceptionally wet spell; the 350m altitude keeps temperatures cool (averaging ~10°C), further slowing evaporation.
Contributing Factors
5
Nearly 85mm in the last 7 days and 156mm over 28 days have kept the rock surface continuously wet with no meaningful dry interval.
28.7mm is falling today with the heaviest showers from 07:00–16:00, ensuring the rock remains soaked through the entire day.
Humidity at 95–99% with 100% cloud cover at 350m means condensation will keep rock wet even between rain showers.
While the exposed position and 25–30 km/h winds would normally aid drying, they are currently driving rain directly onto the W/NW-facing rock and creating dangerous wind-chill for wet climbing.
Rhyolite does not absorb water, so once rain stops and humidity drops, surface drying can be relatively quick — but that window has not arrived.
Recommendations
3
- Do not visit today — the crag is in cloud with heavy rain; conditions are clearly unsuitable.
- Monitor conditions from June 14 onward when a dry day with lower humidity is forecast; a drive-by visual check from the A5 would be worthwhile.
- When conditions improve, test friction carefully on low problems first — the grit-like texture can mask residual dampness in sheltered hollows.
Do Not Climb
92%
8 days ago
Caseg Fraith has received over 80mm of rain in the past 7 days with further rain today and no meaningful dry spell in sight; the rock will be wet and slippery. Despite rhyolite's non-porous nature, the sustained saturation, high humidity, and continued daily precipitation make conditions clearly unsuitable for climbing.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect at 350m means it catches the prevailing SW weather systems head-on, and the last 10 days of persistent Atlantic fronts have kept the crag continually soaked.
- The bouldering here relies heavily on the famous grit-like friction of the rhyolite, which disappears entirely when wet — even a thin moisture film dramatically reduces grip on these rounded, friction-dependent holds.
- At 350m altitude the crag is frequently enveloped in low cloud and mist during unsettled spells, adding ambient moisture on top of direct rainfall and preventing effective drying.
- Roadside access near the A5 makes it easy to drive up and visually check conditions, but the exposed pass can feel significantly colder and wetter than the valley floor — don't be fooled by conditions in Bethesda or Bangor.
Warnings
2
- Do not attempt friction-dependent slab problems — rhyolite becomes extremely slippery when wet and bouldering falls onto wet ground carry additional injury risk.
- The crag may be enveloped in cloud at 350m during this unsettled spell; visibility can drop rapidly on the exposed pass.
Reasoning
With 83mm in the last 7 days, rain every day since June 1st, and further rain today (8.3mm including a 3mm shower forecast at 16:00), the rock surface is thoroughly wet with no opportunity to dry.
Although the exposed position and moderate westerly winds (25–30 km/h) would normally strip surface moisture from rhyolite within a few hours, continuous daily rainfall and 82–94% humidity have prevented any meaningful drying window from developing.
Rhyolite is non-porous and not at risk of structural damage from moisture, so hold breakage and rock integrity are not a concern here.
Early June should be approaching peak season, but this prolonged Atlantic wet spell with below-average temperatures (averaging just 10.7°C) is producing winter-like conditions at altitude; cloud base is frequently at or below crag level.
Contributing Factors
6
Over 83mm in the past 7 days with rain recorded every single day since June 1st means the rock has had zero opportunity to dry.
Average humidity of 88% over the last week, combined with frequent cloud immersion at 350m, keeps surfaces damp even between showers.
Today's forecast includes additional showers (8.3mm total) and tomorrow brings another 6.3mm, extending the wet spell with no dry window.
Winds of 25–30 km/h would normally aid drying on this exposed crag, but are ineffective against continuous rain and near-saturated air.
Caseg Fraith's problems rely on the rhyolite's superb dry friction, which is completely negated by surface moisture, making even nominally easy problems dangerous.
Temperatures averaging just 10.7°C with highs barely reaching 12°C slow evaporation and keep the rock cold and damp.
Recommendations
3
- Wait for a sustained dry spell — conditions will not be suitable until at least June 14th when the forecast finally shows consecutive dry days with lower humidity.
- If visiting the Ogwen Valley during this wet period, consider indoor alternatives or lower-altitude sheltered venues that may dry faster between showers.
- When conditions do improve, prioritise south-facing problems or those on overhanging features, as the NW-facing slabs will be last to dry.
Do Not Climb
92%
9 days ago
Caseg Fraith has received nearly 24mm of rain today on top of over 74mm in the past week, and the rock will be thoroughly wet and slippery. Although a dry window may open mid-afternoon today, the sustained saturation and high humidity mean surfaces will not dry adequately for safe bouldering.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect at 350m means it catches the prevailing SW/W rain directly and receives minimal direct sun for drying, especially during the prolonged wet spell of the past week.
- The boulders sit on an exposed high pass near Tryfan and can be enveloped in low cloud at this altitude, maintaining near-saturation surface moisture even during nominally dry periods.
- The grit-like texture of the rhyolite here provides exceptional friction when dry but becomes treacherously slippery when wet — a critical distinction for bouldering where ground falls are the norm.
- Seepage and run-off from the surrounding hillside can keep landings and lower boulder faces damp long after rain stops, particularly after multi-day wet spells like the current one.
Warnings
2
- Wet rhyolite at Caseg Fraith is extremely slippery — bouldering falls onto saturated ground with reduced friction are a serious injury risk.
- Low cloud may obscure the boulders at 350m and re-wet surfaces without visible rainfall; do not assume a dry forecast means dry rock.
Reasoning
With 23.9mm falling today (mostly overnight/early morning) on top of 74.4mm in the past 7 days, the rock surfaces and surrounding ground are thoroughly saturated.
Despite the exposed position and moderate W winds (~20 km/h), the W/NW aspect receives limited direct sun and humidity remains above 60% even in the driest afternoon hours, meaning surface drying will be partial at best.
Rhyolite is non-porous so there is no structural weakening risk; the sole concern is dangerous friction loss on wet volcanic rock during bouldering.
Early June should be improving but this has been an exceptionally wet period; at 350m, temperatures around 10–12°C and persistent cloud cover significantly slow evaporation.
Contributing Factors
6
74.4mm in the past 7 days culminating in nearly 24mm today means rock surfaces are thoroughly soaked.
Average humidity of 89% over the past week with today's levels only dropping to ~56% at best severely inhibits evaporation.
Sustained winds of 20–25 km/h from the W help strip surface moisture, partially offsetting the humidity.
The W/NW-facing boulders receive limited direct solar heating, reducing the drying effect during afternoon hours.
At 350m near the Ogwen Pass, low cloud and mist can envelop the crag and re-wet surfaces even during dry spells.
A dry period from ~07:00 to ~18:00 may allow some surface drying but is insufficient after this volume of rain.
Recommendations
3
- Do not climb today — the rock will be wet and dangerously slippery for bouldering despite the afternoon dry window.
- Monitor conditions from June 12 onwards when rainfall is forecast to ease and winds pick up, but visually check surfaces before committing.
- If visiting the Ogwen Valley this week, consider the approach walk to check conditions rather than planning a full session — look for dry rock on the most wind-exposed faces.
Do Not Climb
92%
10 days ago
Caseg Fraith is currently saturated after nearly 86mm of rain in the last 7 days, with 17.7mm falling today and another 23.5mm forecast tomorrow. The rock will be wet and dangerously slippery, and there is no meaningful drying window in the 5-day forecast.
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, and at 350m altitude it will frequently be in cloud during this wet spell, further inhibiting any drying.
- The site is roadside near the A5 and easily accessible, but the exposed high pass position means strong SW winds will drive rain directly onto the main boulder faces.
- Despite rhyolite's famous grit-like friction, even minor surface moisture dramatically reduces grip on the crystalline texture — the bouldering here is friction-dependent and intolerant of dampness.
- Seepage and residual moisture can persist in sheltered hollows and north-facing faces for days after heavy rain, even when exposed surfaces appear dry.
Warnings
3
- Wet rhyolite is extremely slippery despite its normally excellent friction — bouldering on damp rock here risks serious falls.
- Strong gusty winds (30–45 km/h forecast) on the exposed pass create additional hazards, particularly on highball problems.
- The surrounding ground will be waterlogged with swollen streams — approach paths may be slippery and boggy.
Reasoning
The rock is thoroughly wet after 85.8mm in the past week including 17.7mm today, with humidity at 95% — every surface will be saturated.
Despite the exposed position and moderate winds, the W/NW aspect, 350m altitude, persistent cloud cover, and near-constant rainfall mean no meaningful drying has occurred or will occur in the near term.
Rhyolite is non-porous and not at risk of structural damage, but friction loss on wet surfaces makes bouldering extremely hazardous.
Early June in Snowdonia is experiencing an unsettled Atlantic pattern with persistent frontal rain; temperatures around 12°C and high humidity severely limit evaporation rates.
Contributing Factors
6
85.8mm in the last 7 days with no consecutive dry days means the rock and surrounding ground are thoroughly soaked.
17.7mm today and 23.5mm forecast tomorrow ensure the rock remains wet with no drying opportunity.
Average humidity of 91% over the past week and 95% today prevents effective surface evaporation even during rain-free hours.
Strong SW winds (25–37 km/h) could aid drying in theory, but they are currently driving moisture-laden air and rain directly onto the W/NW-facing rock.
The W/NW aspect receives limited direct sunlight, meaning even during dry spells the rock dries more slowly than south-facing crags.
The 5-day forecast shows only one marginally drier day (June 10, 0.4mm) before further heavy rain on June 11–12, providing no adequate drying period.
Recommendations
3
- Do not visit Caseg Fraith this week — the rock is wet and the forecast offers no realistic drying window.
- Monitor conditions after June 12; at least 2 consecutive dry days with lower humidity would be needed before the boulders are climbable.
- If you are in the Ogwen area, consider indoor climbing or low-altitude, south-facing venues that may dry faster after any break in the rain.
Do Not Climb
93%
11 days ago
Caseg Fraith is currently soaked after 70.5mm of rain in the last 7 days, with further heavy rain forecast for the next two days. The rock will be wet and extremely slippery, and conditions are not expected to improve meaningfully within the five-day outlook window.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Caseg Fraith's W/NW aspect at 350m means it receives very little direct sun, so even non-porous rhyolite surfaces retain moisture far longer than valley-floor crags — expect lingering dampness in sheltered nooks and on north-facing landings.
- The crag sits on an exposed high pass near Tryfan and is frequently enveloped in low cloud and mist at this altitude, which prevents effective drying even between rain events.
- The renowned grit-like texture of Caseg Fraith rhyolite provides superb friction when dry but becomes treacherously slippery when wet — bouldering falls onto damp landings compound the risk.
- Roadside access from the A5 makes it tempting to 'just check', but at 350m the conditions are often significantly worse than they appear in the valley bottom at Ogwen.
Warnings
3
- Rhyolite is extremely slippery when wet — bouldering on damp Caseg Fraith carries serious risk of uncontrolled falls.
- Low cloud and mist are very likely at 350m given current humidity levels; visibility may be poor and the rock may be wetter than it appears.
- Landings may be waterlogged and soft, increasing the risk of ankle injuries on any fall.
Reasoning
The rock is currently wet: 7.4mm fell today, 70.5mm in the past week, and humidity has averaged 91% — surfaces will be saturated with standing water in many areas.
Despite being an exposed site with moderate winds, the NW aspect, 350m altitude, persistent cloud cover (humidity 93% today), and zero consecutive dry days mean there has been no meaningful drying opportunity.
Rhyolite is non-porous and not at risk of structural damage from moisture, so the concern is purely friction loss and slippery surfaces.
Early June in Snowdonia is experiencing an unseasonably wet and cool spell with temperatures well below average and persistent frontal rainfall — typical summer drying conditions have not materialised.
Contributing Factors
6
70.5mm over the past 7 days with rain on every single day leaves the crag thoroughly wet.
18.9mm and 20.8mm are forecast for the next two days, ensuring the rock stays soaked.
Average humidity of 91% over the past week with 93% today and 96% forecast tomorrow prevents effective surface evaporation.
Strong SW winds (22–37 km/h) would normally aid drying but are negated by continuous rain and near-saturated air.
At 350m with a NW aspect, the crag receives minimal direct sun and is frequently in cloud, greatly slowing any drying.
Rhyolite does not absorb water, so once rain stops and wind dries the surface, conditions can recover relatively quickly — but that window has not arrived.
Recommendations
3
- Avoid Caseg Fraith for at least the next 4–5 days; the prolonged wet spell and continued forecast rain make safe bouldering impossible.
- Monitor conditions from around June 11–12 when the forecast shows a potential drying window, but verify on arrival as high-altitude NW-facing crags can remain damp longer than expected.
- If you're in the Ogwen Valley and desperate to climb, consider lower-altitude, south-facing venues that will dry significantly faster — but check conditions carefully at any crag given the week's rainfall.
Climbing Outlook