Why
- No measurable rain at any of 5 gauges within 5 mi in the last 72 h.
- Rain chance peaks at 9% in the next 12 h.
Rain gauges
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Bars show hourly rain over the last 72 h. Tap a gauge to see its full record on MesoWest.
Local guidance
Community ethic The rock is fragile: don't climb for at least 3 days after a rainstorm. Castle Rock in Pine Canyon and the Wanna Get Away areas close February 1 to July 31 for nesting peregrine falcons. Mountain Project: Pine Canyon ↗
- Rock Sandstone
- Group Fragile when wet: red for 48 h after rain, caution to 72 h (96 h in winter)
Mount Diablo State Park on Mountain Project ↗Bay Area Climbers Coalition ↗
Check the rock yourself
Rain gauges measure rain, not rock moisture. Sandstone is weak when wet and holds water long after the surface looks dry, especially on shaded or seepy faces. If the ground is damp, the rock is too.
Is it actually dry?
Field checks before you tie in
- Is the sand at the base dry? It dries before the rock does; damp sand means wet rock.
- Are the trail and the ground at the cliff base dry? If not, don't climb.
- Look for dark damp patches, moisture behind flakes and inside cracks, and fresh sand on holds.
- Shaded walls, spots under trees and grooves that channel water stay wet much longer.
- Sun and wind dry rock fast; cloudy, calm, humid days slow it down, and winter drying is slow.
- After long, soaking rain the rock can stay wet inches deep. Give it extra time.
- If any part of the route, base included, is wet, pick another climb.
- Not sure? Climb rock that isn't affected by rain, like limestone or granite, until it dries.
Thank you
- Bay Area Climbers Coalition
For volunteer stewardship, bolt replacement and access across the Bay Area.
- Access Fund
For keeping climbing areas open and conserving the climbing environment across the country.
Access Fund is the national climbing advocacy nonprofit. It works alongside local climbing organizations, like the coalitions thanked on each area page, on access, stewardship and education, including how long to wait after rain.
- Weather data
Rain gauges via Synoptic Data (MesoWest) from public and private weather networks. Forecasts from the National Weather Service. Model estimates from Open-Meteo when gauges go quiet.