Mill Valley, CA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Mill Valley, a city in Marin County, California.
Today
80°F
Sunny
Sunny. High near 80, with temperatures falling to around 78 in the afternoon. Southwest wind around 7 mph.
7-day forecast for Mill Valley
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 80°F | Sunny | 7 mph SW | 1% |
| Tonight | 55°F | Partly Cloudy then Patchy Fog | 2 mph SW | 2% |
| Wednesday | 80°F | Mostly Sunny | 2 to 6 mph SW | 2% |
| Wednesday Night | 55°F | Partly Cloudy then Patchy Fog | 2 mph SSW | 0% |
| Thursday | 82°F | Patchy Fog then Mostly Sunny | 0 to 5 mph SW | 0% |
| Thursday Night | 56°F | Mostly Clear | 0 to 3 mph SW | 0% |
| Friday | 88°F | Sunny | 1 to 6 mph WSW | 0% |
| Friday Night | 57°F | Mostly Clear | 1 to 6 mph WSW | 0% |
| Saturday | 86°F | Sunny | 1 to 6 mph SW | 0% |
| Saturday Night | 58°F | Mostly Clear | 5 mph WSW | 0% |
| Sunday | 84°F | Sunny | 2 to 9 mph WSW | 0% |
| Sunday Night | 56°F | Mostly Clear | 5 to 8 mph SW | 0% |
| Monday | 77°F | Sunny | 5 to 9 mph SW | 0% |
| Monday Night | 55°F | Mostly Clear | 3 to 7 mph SW | 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
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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 Aug 4, 2026.