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
46°F
Slight Chance Light Rain then Patchy Fog
A slight chance of rain before 9pm, then patchy fog between 11pm and 1am. Partly cloudy, with a low around 46. Northeast wind around 2 mph. Chance of precipitation is 20%.
7-day forecast for San Ramon
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 46°F | Slight Chance Light Rain then Patchy Fog | 2 mph NE | 15% |
| Wednesday | 65°F | Patchy Fog then Sunny | 2 to 7 mph N | 1% |
| Wednesday Night | 46°F | Mostly Cloudy then Areas Of Fog | 1 mph ENE | 2% |
| Thursday | 69°F | Areas Of Fog then Mostly Sunny | 1 to 5 mph N | 0% |
| Thursday Night | 46°F | Clear | 2 mph N | 0% |
| Friday | 72°F | Sunny | 2 mph N | 0% |
| Friday Night | 48°F | Mostly Clear | 2 mph NNE | 0% |
| Saturday | 74°F | Sunny | 2 mph NE | 0% |
| Saturday Night | 48°F | Mostly Clear | 2 mph N | 0% |
| Sunday | 73°F | Sunny | 2 mph NNW | 0% |
| Sunday Night | 50°F | Partly Cloudy | 2 mph WNW | 0% |
| Monday | 71°F | Mostly Sunny | 0 to 3 mph W | 1% |
| Monday Night | 49°F | Partly Cloudy | 0 to 3 mph NW | 1% |
| Tuesday | 71°F | Sunny | 0 to 3 mph NNW | 5% |
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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Clyde
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Contra Costa Centre
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Danville
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Discovery Bay
East Richmond Heights
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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 Nov 4, 2026.