Historical weather data, all-time temperature records, and monthly climate averages for San Anselmo, CA. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in San Anselmo runs mild and mostly dry, with a typical high of 67° and just a 1-in-4 chance of rain. The date has seen some swings, though — from a scorching 85° back in 1957 to a freezing 32° low in 1918.
San Anselmo's weather has real range: 124 years of records span a brutal 112° summer peak in July 1913 all the way down to 17° on New Year's Eve 1915. The wettest single day on record dropped a staggering 11.56 inches in January 1967 — a reminder that Marin County winters can get serious.
Summers here are warm and reliably dry, peaking in the low-to-mid 80s from July through September — prime time for outdoor everything. Winters cool to the mid-50s and bring the bulk of the rain, with late December being the wettest stretch of the year. Spring and fall are the sweet spot: pleasant temperatures with only occasional showers.