San Ramon, CA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for San Ramon, a city in Contra Costa County, California.
Tonight
55°F
Mostly Clear
Mostly clear, with a low around 55. Southwest wind around 3 mph.
7-day forecast for San Ramon
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 55°F | Mostly Clear | 3 mph SW | 0% |
| Saturday | 84°F | Patchy Fog then Sunny | 1 to 7 mph WSW | 0% |
| Saturday Night | 56°F | Mostly Cloudy | 5 mph WSW | 0% |
| Sunday | 76°F | Partly Sunny | 3 to 7 mph WSW | 3% |
| Sunday Night | 55°F | Mostly Cloudy | 3 to 7 mph WSW | 3% |
| Monday | 78°F | Mostly Sunny | 3 to 8 mph WSW | 0% |
| Monday Night | 55°F | Mostly Clear | 2 to 8 mph WSW | 0% |
| Tuesday | 83°F | Patchy Fog then Sunny | 2 to 7 mph WSW | 0% |
| Tuesday Night | 56°F | Mostly Clear | 0 to 7 mph WSW | 0% |
| Wednesday | 93°F | Sunny | 0 to 5 mph NW | 0% |
| Wednesday Night | 61°F | Mostly Clear | 0 to 5 mph NW | 0% |
| Thursday | 94°F | Sunny | 0 to 7 mph WNW | 0% |
| Thursday Night | 61°F | Mostly Clear | 1 to 7 mph WSW | 0% |
| Friday | 86°F | Sunny | 1 to 8 mph WSW | 0% |
Forecast source: National Weather Service (api.weather.gov) for San Ramon (37.765, -121.932). Updated through the day.
Growing snapshot for San Ramon
Last spring frost
Feb 15
First fall frost
Dec 2
Growing season
292 days
Hardiness zone
9b
More local growing data for San Ramon: nearby ZIP 94582 weather · frost dates · planting calendar · California frost dates
Nearby towns & communities
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Bethel Island
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Castle Hill
Clayton
Clyde
Concord
Contra Costa Centre
Crockett
Danville
Diablo
Discovery Bay
East Richmond Heights
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Hercules
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Lafayette
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Montalvin Manor
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Mountain View
Climate data from the nearest NOAA station, Livermore, Ca (7.5 mi from San Ramon). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.