Guerneville, CA climate
Guerneville has mild winters and pleasant summers. A typical July afternoon reaches 79°, a January night drops to 40°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Guerneville feels like
Winter
Spring
Summer
Fall
Guerneville weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 58° | 40° | 8.9" | 0 | 13 | 0 | 45° – 53° |
| February | 61° | 41° | 8.6" | 0 | 12 | 0 | 46° – 56° |
| March | 63° | 42° | 5.9" | 0 | 11 | 0 | 47° – 58° |
| April | 67° | 43° | 3.0" | 0 | 7 | 0 | 50° – 58° |
| May | 72° | 47° | 1.5" | 0 | 4 | 0 | 55° – 63° |
| June | 77° | 50° | 0.3" | 0 | 2 | 0 | 60° – 66° |
| July | 79° | 52° | 0.0" | 0 | 0 | 0 | 63° – 69° |
| August | 80° | 52° | 0.0" | 0 | 1 | 0 | 63° – 70° |
| September | 80° | 50° | 0.2" | 0 | 2 | 0 | 62° – 69° |
| October | 74° | 47° | 2.0" | 0 | 4 | 0 | 57° – 66° |
| November | 64° | 42° | 4.5" | 0 | 9 | 0 | 47° – 57° |
| December | 57° | 39° | 9.2" | 0 | 13 | 0 | 45° – 53° |
| Year | 69° | 45° | 44.3" | 0.0" | 78 | 0 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Guerneville
Guerneville gets 44 inches of rain and melted snow a year. December is the wettest month and July the driest. Rain or snow falls on about 78 days a year.
About 240 frost-free days a year
In half of years the last 32° night comes by March 20 and the first one by November 13. That leaves about 240 frost-free days for gardens, longer than 88% of U.S. towns.
Heating and cooling a home in Guerneville
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Guerneville, 90% of that work is heating and 10% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
How Guerneville compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Guerneville averaged 1.4° warmer than the 1900s. The biggest change is in January (+2.0°). The shift is larger than in 61% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Guerneville’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. March swings the most: between 1991 and 2020 its average temperature ranged from 47° to 58°. June is the most reliable, staying within 5°.
Common questions about Guerneville’s climate
What is the coldest month in Guerneville?
December, with a typical high of 57° and a low of 39°.
What is the hottest month in Guerneville?
August, with a typical high of 80° and a low of 52°. About 34 days a year reach 90°.
How much snow does Guerneville get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Guerneville?
In half of years the first 32° night comes by November 13, and the last spring frost by March 20.
What is the rainiest month in Guerneville?
December, with 9.2 inches of rain and melted snow. The year totals 44 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Guerneville itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Graton, CA (9 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.