Clayton, CA Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Clayton, a city in Contra Costa County, California.

This Afternoon

87°F

Sunny

Sunny. High near 87, with temperatures falling to around 85 in the afternoon. West wind around 10 mph, with gusts as high as 18 mph.

7-day forecast for Clayton

When	Temp	Forecast	Wind	Precip
This Afternoon	87°F	Sunny	10 mph W	0%
Tonight	56°F	Mostly Clear	3 to 9 mph SW	0%
Saturday	91°F	Sunny	3 to 9 mph WSW	0%
Saturday Night	56°F	Partly Cloudy	5 to 8 mph SW	0%
Sunday	82°F	Partly Sunny	5 to 10 mph SW	1%
Sunday Night	55°F	Mostly Cloudy	7 to 10 mph SW	1%
Monday	84°F	Sunny	7 to 12 mph WSW	0%
Monday Night	55°F	Mostly Clear	5 to 12 mph WSW	0%
Tuesday	88°F	Sunny	5 to 9 mph WSW	0%
Tuesday Night	57°F	Mostly Clear	0 to 9 mph WSW	0%
Wednesday	98°F	Sunny	0 to 6 mph W	0%
Wednesday Night	62°F	Mostly Clear	1 to 6 mph WSW	0%
Thursday	98°F	Sunny	1 to 9 mph W	0%
Thursday Night	62°F	Mostly Clear	3 to 9 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

More local growing data for Clayton: nearby ZIP 94521 weather · frost dates · planting calendar · California frost dates

Nearby towns & communities

Acalanes Ridge Alamo Alhambra Valley Antioch Bay Point Bayview Benicia Bethel Island Blackhawk Brentwood Byron Castle Hill Clyde Concord Contra Costa Centre Crockett Danville Diablo Discovery Bay East Richmond Heights El Cerrito El Sobrante Hercules Knightsen Lafayette Martinez Montalvin Manor Moraga Mountain View Norris Canyon

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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 Sep 19, 2026.