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.

This Afternoon

65°F

Sunny

Sunny, with a high near 65. West northwest wind around 17 mph, with gusts as high as 23 mph.

7-day forecast for Foster City

When	Temp	Forecast	Wind	Precip
This Afternoon	65°F	Sunny	17 mph WNW	0%
Tonight	59°F	Mostly Clear	6 to 16 mph WSW	0%
Saturday	67°F	Mostly Sunny	3 to 16 mph W	0%
Saturday Night	59°F	Mostly Cloudy	7 to 14 mph W	1%
Sunday	63°F	Mostly Cloudy	7 to 14 mph W	4%
Sunday Night	59°F	Mostly Cloudy	6 to 14 mph WSW	4%
Monday	67°F	Mostly Sunny	6 to 13 mph WSW	0%
Monday Night	59°F	Partly Cloudy	3 to 13 mph WSW	0%
Tuesday	72°F	Sunny	3 to 13 mph WSW	0%
Tuesday Night	59°F	Mostly Clear	2 to 13 mph WSW	0%
Wednesday	79°F	Sunny	2 to 13 mph W	0%
Wednesday Night	61°F	Mostly Clear	2 to 13 mph WSW	0%
Thursday	80°F	Sunny	2 to 14 mph W	0%
Thursday Night	61°F	Partly Cloudy	3 to 14 mph W	0%

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

Nearby towns & communities

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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 Sep 19, 2026.