Clayton, CA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Clayton, a city in Contra Costa County, California.
Today
103°F
Sunny
Sunny. High near 103, with temperatures falling to around 99 in the afternoon. West southwest wind 6 to 12 mph, with gusts as high as 21 mph.
7-day forecast for Clayton
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 103°F | Sunny | 6 to 12 mph WSW | 0% |
| Tonight | 58°F | Clear | 6 to 10 mph WSW | 0% |
| Wednesday | 98°F | Sunny | 7 to 10 mph WSW | 0% |
| Wednesday Night | 58°F | Clear | 6 to 10 mph WSW | 0% |
| Thursday | 96°F | Sunny | 6 to 12 mph WSW | 0% |
| Thursday Night | 60°F | Clear | 6 to 12 mph WSW | 0% |
| Friday | 101°F | Sunny | 6 to 12 mph WSW | 0% |
| Friday Night | 62°F | Clear | 7 to 12 mph WSW | 0% |
| Saturday | 101°F | Sunny | 7 to 12 mph WSW | 0% |
| Saturday Night | 64°F | Mostly Clear | 8 to 12 mph WSW | 0% |
| Sunday | 96°F | Sunny | 8 to 14 mph SW | 0% |
| Sunday Night | 59°F | Mostly Clear | 14 mph SW | 0% |
| Monday | 90°F | Sunny | 14 mph WSW | 0% |
| Monday Night | 57°F | Mostly Clear | 9 to 14 mph WSW | 0% |
Forecast source: National Weather Service (api.weather.gov) for Clayton (37.940, -121.930). Updated through the day.
Growing snapshot for Clayton
Last spring frost
Jan 9
First fall frost
Dec 14
Growing season
343 days
Hardiness zone
9b
More local growing data for Clayton: nearby ZIP 94521 weather · frost dates · planting calendar · California frost dates
Nearby towns & communities
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Benicia
Bethel Island
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Byron
Castle Hill
Clyde
Concord
Contra Costa Centre
Crockett
Danville
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Discovery Bay
East Richmond Heights
El Cerrito
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Knightsen
Lafayette
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Mountain View
Norris Canyon
Climate data from the nearest NOAA station, Concord Buchanan Fld, Ca (5.4 mi from Clayton). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.