Mill Valley, CA Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Mill Valley, a city in Marin County, California.

This Afternoon

78°F

Sunny

Sunny. High near 78, with temperatures falling to around 76 in the afternoon. West wind around 8 mph.

7-day forecast for Mill Valley

When	Temp	Forecast	Wind	Precip
This Afternoon	78°F	Sunny	8 mph W	0%
Tonight	55°F	Mostly Clear then Patchy Fog	1 to 7 mph W	0%
Saturday	80°F	Patchy Fog then Sunny	1 to 7 mph SW	0%
Saturday Night	55°F	Partly Cloudy	3 mph W	0%
Sunday	71°F	Partly Sunny	3 to 7 mph WSW	1%
Sunday Night	55°F	Mostly Cloudy	3 mph WSW	1%
Monday	71°F	Patchy Fog then Mostly Sunny	2 to 7 mph SW	0%
Monday Night	56°F	Partly Cloudy	2 to 6 mph SW	0%
Tuesday	76°F	Mostly Sunny	5 mph SW	0%
Tuesday Night	56°F	Mostly Clear	0 to 5 mph W	0%
Wednesday	86°F	Patchy Fog then Sunny	2 mph NW	0%
Wednesday Night	58°F	Mostly Clear	2 mph NW	0%
Thursday	86°F	Sunny	0 to 3 mph WSW	0%
Thursday Night	59°F	Partly Cloudy	3 mph W	0%

Forecast source: National Weather Service (api.weather.gov) for Mill Valley (37.908, -122.542). Updated through the day.

Growing snapshot for Mill Valley

Last spring frost

Jan 16

First fall frost

Dec 18

Growing season

334 days

Hardiness zone

10a

More local growing data for Mill Valley: nearby ZIP 94939 weather · frost dates · planting calendar · California frost dates

Nearby towns & communities

Alto Belvedere Black Point-Green Point Bolinas Corte Madera Dillon Beach Fairfax Inverness Kentfield Lagunitas-Forest Knolls Larkspur Lucas Valley-Marinwood Marin City Muir Beach Nicasio Novato Petaluma Center Point Reyes Station Ross San Anselmo San Francisco San Geronimo San Rafael Santa Venetia Sausalito Sleepy Hollow Stinson Beach Strawberry Tamalpais-Homestead Valley Tiburon

All California locations ›

Climate data from the nearest NOAA station, Kentfield, Ca (1.4 mi from Mill Valley). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 18, 2026.