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
63°F
Light Rain
Rain. Mostly cloudy. High near 63, with temperatures falling to around 59 in the afternoon. South southwest wind 0 to 15 mph, with gusts as high as 23 mph. Chance of precipitation is 90%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast for Mill Valley
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 63°F | Light Rain | 0 to 15 mph SSW | 90% |
| Tonight | 49°F | Chance Light Rain then Mostly Cloudy | 1 to 7 mph E | 44% |
| Wednesday | 67°F | Sunny | 2 to 7 mph N | 3% |
| Wednesday Night | 50°F | Partly Cloudy | 1 to 7 mph NW | 0% |
| Thursday | 71°F | Sunny | 2 mph NNW | 0% |
| Thursday Night | 50°F | Mostly Clear | 1 mph NNW | 0% |
| Friday | 72°F | Sunny | 1 mph N | 0% |
| Friday Night | 50°F | Mostly Clear | 1 mph N | 0% |
| Saturday | 76°F | Sunny | 0 to 6 mph NNE | 0% |
| Saturday Night | 51°F | Mostly Clear | 2 mph NW | 0% |
| Sunday | 74°F | Mostly Sunny | 3 mph NNW | 0% |
| Sunday Night | 53°F | Partly Cloudy | 1 mph NW | 0% |
| Monday | 72°F | Partly Sunny | 3 mph WNW | 1% |
| Monday Night | 51°F | Partly Cloudy | 2 mph NW | 2% |
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
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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 Nov 3, 2026.