San Geronimo, CA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for San Geronimo, a community in Marin County, California.
Overnight
52°F
Mostly Clear
Mostly clear. Low around 52, with temperatures rising to around 55 overnight. South southwest wind around 3 mph.
7-day forecast for San Geronimo
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 52°F | Mostly Clear | 3 mph SSW | 0% |
| Tuesday | 87°F | Haze then Sunny | 3 to 7 mph SSW | 1% |
| Tuesday Night | 53°F | Partly Cloudy | 5 mph SW | 2% |
| Wednesday | 79°F | Mostly Sunny | 3 to 7 mph SW | 3% |
| Wednesday Night | 53°F | Patchy Fog | 2 to 6 mph WSW | 0% |
| Thursday | 76°F | Patchy Fog then Mostly Sunny | 2 to 6 mph WSW | 0% |
| Thursday Night | 53°F | Partly Cloudy | 2 to 6 mph W | 0% |
| Friday | 82°F | Sunny | 2 to 7 mph W | 0% |
| Friday Night | 54°F | Partly Cloudy | 2 to 7 mph WSW | 0% |
| Saturday | 81°F | Sunny | 2 to 7 mph WSW | 0% |
| Saturday Night | 57°F | Mostly Clear | 7 mph W | 0% |
| Sunday | 79°F | Sunny | 5 to 8 mph W | 0% |
| Sunday Night | 54°F | Mostly Clear | 5 to 8 mph W | 0% |
| Monday | 71°F | Sunny | 5 to 8 mph SW | 0% |
Forecast source: National Weather Service (api.weather.gov) for San Geronimo (38.007, -122.663). Updated through the day.
Growing snapshot for San Geronimo
Last spring frost
Jan 11
First fall frost
Dec 21
Growing season
349 days
Hardiness zone
9b
More local growing data for San Geronimo: nearby ZIP 94963 weather · frost dates · planting calendar · California frost dates
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Climate data from the nearest NOAA station, San Rafael Civic Ctr, Ca (7 mi from San Geronimo). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.