California · Rock climbing · Walnut Creek

Mammoth Rock

Mammoth Rock in California offers 5 climbing routes across 3 difficulty grades, with sport and trad options.

Photo: @bastique, CC BY-SA 2.0 (via Flickr)

5 routes

5.7 – 5.11a

Sport · Trad

Best time to visit Mammoth Rock

Best months: October–June. Best months have typical highs of 55–85 °F, lows of 30 °F or warmer (32 °F where the station doesn't record snow), at most one snowy day and no more than 12 wet days.

Jan
58° / 42°
10 wet
Feb
63° / 44°
10 wet
Mar
68° / 47°
8 wet
Apr
72° / 49°
5 wet
May
78° / 53°
3 wet
Jun
85° / 57°
1 wet
Jul
88° / 58°
0 wet
Aug
88° / 59°
0 wet
Sep
86° / 58°
1 wet
Oct
78° / 53°
3 wet
Nov
67° / 46°
6 wet
Dec
59° / 41°
9 wet

Typical high / low (°F) and days with rain or snow, 1991–2020. Measured at Concord Wwtp, CA, 8.4 mi away at 40 ft. The station sits about 500 ft lower than this place, so expect it a little cooler here. Source: NOAA NCEI U.S. Climate Normals 1991–2020.

Mammoth Rock is a climbing area in Mount Diablo State Park in California, managed by State Park and Recreation. It sits among several other climbing areas and hiking trails, which makes it easy to pair with other outings in the park. The most comfortable months for a visit are spring and fall. Typical averages from a nearby weather station run from highs around 72°F in April to 78°F in October, with only a few wet days in each. That station sits a few hundred feet lower than the rock, so temperatures on the cliff may run slightly cooler. Five routes are listed, with four sport routes and one trad route. The sport routes range from 5.10c to 5.11a, and the trad route, Peregrine/Raptors nest, is 5.7. Among the named climbs are Bridge of Sighs at 5.10c and Boromir at 5.11a. Pine Canyon, Flintstone Rock and The Rock of Ages are all climbing areas about 0.1 mile away, and the Buckeye Ravine Trail is a short hike at the same distance.