Likely dry

Why

• No measurable rain at any of 4 gauges within 4 mi in the last 72 h.
• Rain chance peaks at 2% in the next 12 h.

Rain gauges

Bars show hourly rain over the last 72 h. Tap a gauge to see its full record on MesoWest.

Local guidance

Park guidance California State Parks: routes can be changed dramatically if climbed while the rock is wet, as this sandstone becomes much more fragile when damp. After heavy storms it can stay wet for days. CA State Parks: Castle Rock ↗

• Rock Vaqueros Sandstone
• Group Fragile when wet: red for 48 h after rain, caution to 72 h (96 h in winter)

Castle Rock State Park on Mountain Project ↗Bay Area Climbers Coalition ↗

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.

Learn more

• Wet Rock Police: Castle Rock ↗ by Grant Mercer and contributorsTime since the last rain near Castle Rock and local wet-rock guidance.
• Castle Rock State Park ↗ by California State ParksPark rules, including staying off damp sandstone.
• How to Assess Sandstone After Rain or Snow ↗ by Access FundWhy western sandstone can lose up to 75% of its strength when wet, and how long to wait after rain or snow.

Thank you

• Bay Area Climbers Coalition

  For volunteer stewardship, bolt replacement and access across the Bay Area.

  Facebook group ↗Instagram ↗

• Grant Mercer & Wet Rock Police contributors

  For Wet Rock Police's Castle Rock page and its time-since-rain tracking.

• 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.

  How to assess sandstone 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.