San Geronimo, CA Weather & Growing Conditions
Overnight
48°F
Chance Light Rain
A chance of rain before 4am. Partly cloudy. Low around 48, with temperatures rising to around 50 overnight. East wind around 6 mph. Chance of precipitation is 30%.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 48°F | Chance Light Rain | 6 mph E | 25% |
| Wednesday | 63°F | Sunny | 3 to 9 mph NNE | 2% |
| Wednesday Night | 50°F | Mostly Cloudy | 5 to 8 mph NW | 2% |
| Thursday | 68°F | Mostly Sunny | 5 mph NW | 0% |
| Thursday Night | 48°F | Mostly Clear | 5 mph NNW | 0% |
| Friday | 69°F | Sunny | 5 mph N | 0% |
| Friday Night | 50°F | Mostly Clear | 0 to 5 mph NNW | 0% |
| Saturday | 71°F | Sunny | 1 to 5 mph NE | 0% |
| Saturday Night | 50°F | Mostly Clear | 3 mph NW | 0% |
| Sunday | 68°F | Mostly Sunny | 5 mph NW | 0% |
| Sunday Night | 52°F | Partly Cloudy | 5 mph NW | 0% |
| Monday | 66°F | Mostly Sunny | 2 to 6 mph NW | 2% |
| Monday Night | 51°F | Partly Cloudy | 2 to 6 mph NW | 2% |
| Tuesday | 66°F | Sunny | 5 mph NNW | 8% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for San Geronimo, CA
Last spring frost
Jan 11
First fall frost
Dec 21
Growing season
349 days
Hardiness zone
9b
Explore more for San Geronimo, CA: full frost dates · planting calendar · California frost dates
Climate data from the nearest NOAA station, San Rafael Civic Ctr, Ca (7 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.