Santa Rosa, CA climate
Santa Rosa has mild winters and pleasant summers. A typical July afternoon reaches 84°, a January night drops to 38°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Santa Rosa feels like
Winter
Spring
Summer
Fall
Santa Rosa 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° | 38° | 6.1" | 0 | 14 | 0 | 45° – 52° |
| February | 62° | 40° | 6.2" | 0 | 13 | 0 | 46° – 56° |
| March | 65° | 41° | 4.5" | 0 | 12 | 0 | 47° – 59° |
| April | 69° | 43° | 2.1" | 0 | 8 | 0 | 51° – 60° |
| May | 75° | 46° | 1.2" | 0 | 5 | 0 | 56° – 66° |
| June | 81° | 50° | 0.3" | 0 | 1 | 0 | 62° – 68° |
| July | 84° | 51° | 0.0" | 0 | 0 | 0 | 65° – 70° |
| August | 84° | 51° | 0.0" | 0 | 0 | 0 | 65° – 72° |
| September | 84° | 50° | 0.1" | 0 | 1 | 0 | 63° – 70° |
| October | 77° | 46° | 1.6" | 0 | 4 | 0 | 59° – 67° |
| November | 65° | 41° | 3.4" | 0 | 9 | 0 | 47° – 57° |
| December | 58° | 37° | 6.7" | 0 | 13 | 0 | 44° – 52° |
| Year | 72° | 44° | 32.1" | 0.0" | 81 | 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 Santa Rosa
Santa Rosa gets 32 inches of rain and melted snow a year. December is the wettest month and July the driest. Rain or snow falls on about 81 days a year.
About 279 frost-free days a year
In half of years the last 32° night comes by February 25 and the first one by December 1. That leaves about 279 frost-free days for gardens, longer than 93% of U.S. towns.
Heating and cooling a home in Santa Rosa
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Santa Rosa, 86% of that work is heating and 14% 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.
Santa Rosa and its neighbors
Santa Rosa borders 3 towns with climate data. January nights across them vary by 1.2°. Larkfield-Wikiup has both the coldest January nights (38°) and the hottest July afternoons (84°). Santa Rosa’s January low is 38° and its July high 84°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Santa Rosa 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 Santa Rosa averaged 1.5° warmer than the 1900s. The biggest change is in January (+2.3°). The shift is larger than in 69% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Santa Rosa’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 59°. July is the most reliable, staying within 6°.
Common questions about Santa Rosa’s climate
What is the coldest month in Santa Rosa?
December, with a typical high of 58° and a low of 37°.
What is the hottest month in Santa Rosa?
August, with a typical high of 84° and a low of 51°. About 26 days a year reach 90°.
How much snow does Santa Rosa get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Santa Rosa?
In half of years the first 32° night comes by December 1, and the last spring frost by February 25.
What is the rainiest month in Santa Rosa?
December, with 6.7 inches of rain and melted snow. The year totals 32 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Santa Rosa itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Santa Rosa, CA (1 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.