Portola Valley, CA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Portola Valley, a town in San Mateo County, California.
Overnight
56°F
Mostly Clear
Mostly clear, with a low around 56. South southwest wind around 2 mph.
7-day forecast for Portola Valley
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 56°F | Mostly Clear | 2 mph SSW | 0% |
| Tuesday | 92°F | Haze then Sunny | 1 to 5 mph SW | 0% |
| Tuesday Night | 56°F | Clear | 1 to 5 mph SW | 0% |
| Wednesday | 89°F | Sunny | 1 to 5 mph WSW | 0% |
| Wednesday Night | 57°F | Mostly Clear | 0 to 5 mph WSW | 0% |
| Thursday | 87°F | Sunny | 0 to 5 mph SW | 0% |
| Thursday Night | 58°F | Mostly Clear | 0 to 5 mph NW | 0% |
| Friday | 91°F | Sunny | 0 to 5 mph NW | 0% |
| Friday Night | 60°F | Mostly Clear | 1 to 5 mph NW | 0% |
| Saturday | 91°F | Sunny | 0 to 5 mph WNW | 0% |
| Saturday Night | 61°F | Mostly Clear | 5 mph W | 0% |
| Sunday | 86°F | Sunny | 2 to 6 mph W | 0% |
| Sunday Night | 56°F | Mostly Clear | 6 mph W | 0% |
| Monday | 80°F | Sunny | 3 to 7 mph WSW | 0% |
Forecast source: National Weather Service (api.weather.gov) for Portola Valley (37.365, -122.233). Updated through the day.
Growing snapshot for Portola Valley
Last spring frost
Feb 25
First fall frost
Nov 25
Growing season
274 days
Hardiness zone
9b
More local growing data for Portola Valley: nearby ZIP 94028 weather · frost dates · planting calendar · California frost dates
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San Mateo
South San Francisco
West Menlo Park
Woodside
Climate data from the nearest NOAA station, Woodside Fire Stn 1, Ca (4.4 mi from Portola Valley). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.