National Weather Service Forecast for: Guerneville CA
Issued by: National Weather Service San Francisco Bay Area/Monterey, CA
Updated: 12:46 am PDT Aug 20, 2026
 
Overnight

Overnight: Areas of fog. Otherwise, mostly cloudy, with a low around 54. Calm wind.
Areas Fog

 Thursday

Thursday: Areas of fog before 11am. Otherwise, partly sunny, with a high near 80. Calm wind becoming south southwest around 6 mph in the afternoon.
Areas Fog
then Mostly
Cloudy
 Thursday
Night
Thursday Night: Cloudy, with a low around 55. Calm wind.
Cloudy

 Friday

Friday: Cloudy through mid morning, then gradual clearing, with a high near 80. Calm wind becoming west southwest 5 to 7 mph in the afternoon.
Gradual
Clearing
 Friday
Night
Friday Night: Patchy fog after 3am. Otherwise, mostly clear, with a low around 52. West wind around 6 mph becoming calm in the evening.
Mostly Clear
then Patchy
Fog
 Saturday

Saturday: Patchy fog before 8am. Otherwise, sunny, with a high near 83.
Patchy Fog
then Sunny
 Saturday
Night
Saturday Night: Mostly clear, with a low around 54.
Mostly Clear

 Sunday

Sunday: Patchy fog before 8am. Otherwise, mostly sunny, with a high near 83.
Patchy Fog
then Sunny
 Sunday
Night
Sunday Night: Patchy fog after 1am. Otherwise, partly cloudy, with a low around 53.
Mostly Clear
then Patchy
Fog
Lo 54 °F Hi 80 °F Lo 55 °F Hi 80 °F Lo 52 °F Hi 83 °F Lo 54 °F Hi 83 °F Lo 53 °F

 

Overnight
 
 Areas of fog. Otherwise, mostly cloudy, with a low around 54. Calm wind.
Thursday
 
 Areas of fog before 11am. Otherwise, partly sunny, with a high near 80. Calm wind becoming south southwest around 6 mph in the afternoon.
Thursday Night
 
 Cloudy, with a low around 55. Calm wind.
Friday
 
 Cloudy through mid morning, then gradual clearing, with a high near 80. Calm wind becoming west southwest 5 to 7 mph in the afternoon.
Friday Night
 
 Patchy fog after 3am. Otherwise, mostly clear, with a low around 52. West wind around 6 mph becoming calm in the evening.
Saturday
 
 Patchy fog before 8am. Otherwise, sunny, with a high near 83.
Saturday Night
 
 Mostly clear, with a low around 54.
Sunday
 
 Patchy fog before 8am. Otherwise, mostly sunny, with a high near 83.
Sunday Night
 
 Patchy fog after 1am. Otherwise, partly cloudy, with a low around 53.
Monday
 
 Areas of fog before 10am. Otherwise, mostly sunny, with a high near 77.
Monday Night
 
 Patchy fog. Otherwise, partly cloudy, with a low around 52.
Tuesday
 
 Areas of fog. Otherwise, mostly sunny, with a high near 79.
Tuesday Night
 
 Patchy fog. Otherwise, partly cloudy, with a low around 53.
Wednesday
 
 Patchy fog. Otherwise, mostly sunny, with a high near 82.

 

Forecast from NOAA-NWS for Guerneville CA.