54°F
Mainly Clear
San Francisco, Napa Valley
Updated 2:09 AM PT
Feels Like
52°F
Humidity
94%
Wind
8 mph WSW
Precipitation
None
Today's High
64°F
Today's Low
54°F
Sunrise
6:39 AM
Sunset
7:40 PM
Hourly Forecast
2 AM
54°
2%
3 AM
54°
2%
4 AM
54°
1%
5 AM
55°
2%
6 AM
55°
2%
7 AM
56°
2%
8 AM
56°
2%
9 AM
57°
1%
10 AM
59°
2%
11 AM
59°
1%
12 PM
61°
1%
1 PM
63°
1%
7-Day Forecast
Today
Foggy
64°
54°
💨 15 mph
Tomorrow
Overcast
66°
58°
💨 12 mph
Wed, Sep 2
Light Drizzle
71°
60°
💧 0.01"
💨 12 mph
Thu, Sep 3
Overcast
71°
60°
💨 11 mph
Fri, Sep 4
Light Drizzle
66°
58°
💧 0.01"
💨 16 mph
Sat, Sep 5
Partly Cloudy
70°
56°
💨 10 mph
Sun, Sep 6
Overcast
73°
57°
💨 8 mph
Napa Valley Weather Notes
San Francisco Bay Area sits at the heart of the Napa Valley floor, sheltered by the Mayacamas Mountains to the west and the Vaca Range to the east. The valley's fog-channeling geography creates a natural air-conditioning effect — cool Pacific fog rolls in from San Pablo Bay each evening, burning off by mid-morning. Summer afternoons typically reach the 90s°F while winter lows can dip into the low 30s. The peak growing season runs May through October, and frost risk is highest December through February.