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
62°F
Light Rain Likely
Rain likely. Partly sunny, with a high near 62. South southwest wind around 9 mph. Chance of precipitation is 60%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Foster City
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 62°F | Light Rain Likely | 9 mph SSW | 59% |
| Tonight | 55°F | Chance Light Rain then Mostly Cloudy | 6 to 10 mph ESE | 41% |
| Wednesday | 63°F | Sunny | 5 to 17 mph NNW | 2% |
| Wednesday Night | 56°F | Mostly Cloudy | 2 to 17 mph NNW | 0% |
| Thursday | 64°F | Sunny | 2 to 10 mph NNW | 0% |
| Thursday Night | 56°F | Mostly Clear | 3 to 10 mph WSW | 0% |
| Friday | 68°F | Sunny | 3 to 7 mph NNE | 0% |
| Friday Night | 55°F | Mostly Clear | 2 to 7 mph W | 0% |
| Saturday | 72°F | Sunny | 2 to 7 mph NNE | 0% |
| Saturday Night | 56°F | Mostly Clear | 2 to 8 mph WNW | 0% |
| Sunday | 70°F | Mostly Sunny | 2 to 8 mph NW | 0% |
| Sunday Night | 56°F | Partly Cloudy | 2 to 8 mph W | 0% |
| Monday | 68°F | Partly Sunny | 2 to 10 mph WNW | 1% |
| Monday Night | 56°F | Mostly Cloudy | 2 to 10 mph WNW | 2% |
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.