Foster City, CA Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Foster City, a city in San Mateo County, California.

Today

63°F

Sunny

Sunny, with a high near 63. Northwest wind 5 to 18 mph, with gusts as high as 24 mph.

7-day forecast for Foster City

When	Temp	Forecast	Wind	Precip
Today	63°F	Sunny	5 to 18 mph NW	1%
Tonight	55°F	Mostly Cloudy	2 to 20 mph WNW	1%
Thursday	64°F	Sunny	3 to 12 mph NNW	0%
Thursday Night	55°F	Mostly Clear	3 to 12 mph SSW	0%
Friday	65°F	Mostly Sunny	3 to 9 mph NNE	0%
Friday Night	56°F	Mostly Clear	2 to 9 mph S	0%
Saturday	66°F	Sunny	2 to 7 mph N	0%
Saturday Night	57°F	Mostly Clear	2 to 7 mph WNW	0%
Sunday	66°F	Mostly Sunny	2 to 9 mph NW	0%
Sunday Night	58°F	Partly Cloudy	1 to 9 mph W	0%
Monday	65°F	Mostly Sunny	2 to 12 mph W	0%
Monday Night	57°F	Partly Cloudy	2 to 12 mph WSW	1%
Tuesday	65°F	Mostly Sunny	2 to 9 mph W	1%
Tuesday Night	57°F	Partly Cloudy	3 to 9 mph W	9%

Forecast source: National Weather Service (api.weather.gov) for Foster City (37.565, -122.251). Updated through the day.

Growing snapshot for Foster City

Last spring frost

Jan 17

First fall frost

Dec 12

Growing season

333 days

Hardiness zone

10a

More local growing data for Foster City: nearby ZIP 94404 weather · frost dates · planting calendar · California frost dates

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Climate data from the nearest NOAA station, Redwood City, Ca (5.7 mi from Foster City). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.