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.

This Afternoon

81°F

Sunny

Sunny. High near 81, with temperatures falling to around 76 in the afternoon. West northwest wind 3 to 7 mph.

7-day forecast for Portola Valley

When	Temp	Forecast	Wind	Precip
This Afternoon	81°F	Sunny	3 to 7 mph WNW	0%
Tonight	54°F	Partly Cloudy	3 to 7 mph WSW	0%
Sunday	73°F	Mostly Cloudy	2 to 6 mph WSW	2%
Sunday Night	54°F	Mostly Cloudy	2 to 6 mph WSW	2%
Monday	75°F	Mostly Sunny	5 mph WSW	1%
Monday Night	54°F	Partly Cloudy	5 mph WSW	1%
Tuesday	77°F	Mostly Sunny	1 to 5 mph W	1%
Tuesday Night	54°F	Mostly Clear	1 to 5 mph W	0%
Wednesday	87°F	Sunny	1 to 5 mph W	0%
Wednesday Night	60°F	Mostly Clear	0 to 5 mph NNW	0%
Thursday	90°F	Sunny	0 to 5 mph NW	0%
Thursday Night	60°F	Mostly Clear	5 mph W	0%
Friday	84°F	Sunny	2 to 7 mph W	0%
Friday Night	56°F	Mostly Clear	2 to 7 mph W	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

More local growing data for Portola Valley: nearby ZIP 94028 weather · frost dates · planting calendar · California frost dates

Nearby towns & communities

Atherton Baywood Park Belmont Brisbane Broadmoor Burlingame Colma Daly City El Granada Emerald Lake Hills Foster City Half Moon Bay Highlands Hillsborough La Honda Ladera Loma Mar Millbrae Montara Moss Beach North Fair Oaks Pacifica Pescadero Redwood City San Bruno San Carlos San Mateo South San Francisco West Menlo Park Woodside

All California locations ›

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 Sep 20, 2026.