- WinterDec–Feb40°60°
- December39°58°
- January40°59°
- February41°62°
- SpringMar–May45°69°
- March43°65°
- April45°69°
- May49°73°
- SummerJun–Aug53°81°
- June52°79°
- July53°81°
- August53°83°
- AutumnSep–Nov48°75°
- September52°83°
- October49°78°
- November43°66°
Santa Rosa, CA Weather by Month and Climate Averages
Santa Rosa, CA gets 31.5 in of precipitation a year over about 79 rainy days. August is the warmest month (average high 83°F) and December the coldest (average low 39°F).
Santa Rosa climate at a glance
Mediterranean climate
Santa Rosa, CA has warm summers and mild winters. Daytime highs range from about 58°F in December to 83°F in August. December is usually the wettest month. The most comfortable time to visit is typically February to June and October to November, when daytime highs sit near 70°F.
How much rain does Santa Rosa get?
Santa Rosa gets 31.5 in of precipitation in an average year, spread over about 79 days with measurable rain. That is fewer rainy days than 58% of the US.
December is the wettest month, with 6.5 in. July is the driest, with 0.0 in. January has the most rainy days, about 14.
The longest dry spell in the last five years lasted 46 days, to September 8, 2025.
See where Santa Rosa ranks: rainiest cities in the US, US cities with the most rainy days, rainiest cities in California.
Santa Rosa weather by month
Santa Rosa weather in January
In January, Santa Rosa averages a high of 59°F and a low of 40°F. It gets 5.8 in of precipitation over about 14 rainy days. The sun is out about 36% of daylight hours. The January record high is 84°F (2009) and the record low is 22°F (1979).
Santa Rosa weather in February
In February, Santa Rosa averages a high of 62°F and a low of 41°F. It gets 6.4 in of precipitation over about 12 rainy days. The sun is out about 56% of daylight hours. The February record high is 83°F (2011) and the record low is 23°F (1989). February is one of the most comfortable months to visit.
Santa Rosa weather in March
In March, Santa Rosa averages a high of 65°F and a low of 43°F. It gets 4.3 in of precipitation over about 12 rainy days. The sun is out about 50% of daylight hours. The March record high is 92°F (2026) and the record low is 28°F (1971). March is one of the most comfortable months to visit.
Santa Rosa weather in April
In April, Santa Rosa averages a high of 69°F and a low of 45°F. It gets 2.0 in of precipitation over about 8 rainy days. The sun is out about 63% of daylight hours. The April record high is 98°F (1981) and the record low is 30°F (1976). April is one of the most comfortable months to visit.
Santa Rosa weather in May
In May, Santa Rosa averages a high of 73°F and a low of 49°F. It gets 1.3 in of precipitation over about 5 rainy days. The sun is out about 72% of daylight hours. The May record high is 101°F (1982) and the record low is 32°F (1977). May is one of the most comfortable months to visit.
Santa Rosa weather in June
In June, Santa Rosa averages a high of 79°F and a low of 52°F. It gets 0.3 in of precipitation over about 1 rainy days. The sun is out about 75% of daylight hours. The June record high is 108°F (2000) and the record low is 34°F (2011). June is one of the most comfortable months to visit.
Santa Rosa weather in July
In July, Santa Rosa averages a high of 81°F and a low of 53°F. It gets 0.0 in of precipitation over about 0 rainy days. The sun is out about 87% of daylight hours. The July record high is 110°F (1972) and the record low is 42°F (2012).
Santa Rosa weather in August
In August, Santa Rosa averages a high of 83°F and a low of 53°F. It gets 0.0 in of precipitation over about 0 rainy days. The sun is out about 83% of daylight hours. The August record high is 107°F (2010) and the record low is 30°F (2011).
Santa Rosa weather in September
In September, Santa Rosa averages a high of 83°F and a low of 52°F. It gets 0.1 in of precipitation over about 1 rainy days. The sun is out about 79% of daylight hours. The September record high is 115°F (2022) and the record low is 37°F (2012).
Santa Rosa weather in October
In October, Santa Rosa averages a high of 78°F and a low of 49°F. It gets 1.6 in of precipitation over about 4 rainy days. The sun is out about 70% of daylight hours. The October record high is 105°F (1980) and the record low is 30°F (1970). October is one of the most comfortable months to visit.
Santa Rosa weather in November
In November, Santa Rosa averages a high of 66°F and a low of 43°F. It gets 3.3 in of precipitation over about 9 rainy days. The sun is out about 56% of daylight hours. The November record high is 88°F (1976) and the record low is 25°F (2019). November is one of the most comfortable months to visit.
Santa Rosa weather in December
In December, Santa Rosa averages a high of 58°F and a low of 39°F. It gets 6.5 in of precipitation over about 13 rainy days. The sun is out about 35% of daylight hours. The December record high is 78°F (1999) and the record low is 16°F (1972).
Sunshine, humidity and wind in Santa Rosa
July is the sunniest month in Santa Rosa, with sunshine about 87% of daylight hours. December is the cloudiest, at 35%. Over the year the sun shines about 64% of daylight hours. Santa Rosa is sunnier than 91% of the US.
Humidity peaks in December at 78% and is lowest in June at 52%.
Santa Rosa has about 27 days a year above 90°F. Santa Rosa is cooler than 53% of the US.
See where Santa Rosa ranks: sunniest cities in the US, cloudiest cities in the US, hottest cities in the US.
First and last freeze in Santa Rosa
The first fall freeze in Santa Rosa typically comes around November 27, and the last spring freeze around February 20. That leaves a frost-free growing season of about 280 days.
Santa Rosa weather records
The hottest temperature on record at the Santa Rosa station is 115°F, on September 6, 2022. The coldest is 16°F, on December 9, 1972.
The wettest day on record brought 7.8 in of rain, on October 24, 2021.
35 all-time records have been set at the station since 1970.
The annual mean temperature has changed by +0.3°F per decade since 1970.
The best time to visit Santa Rosa
The most comfortable time to visit is typically February to June and October to November, when daytime highs sit near 70°F.
Winter (December–February) is mild, with average highs around 60°F and lows near 40°F.
Spring (March–May) is warm, with average highs around 69°F and lows near 45°F.
Summer (June–August) is warm, with average highs around 81°F and lows near 53°F.
Autumn (September–November) is warm, with average highs around 75°F and lows near 48°F.
Monthly climate
| Month | Precip | Rain days | Humidity | Sunshine | Sea temp | Record high | Record low |
|---|---|---|---|---|---|---|---|
| January | 5.8 in | 14 | 75% | 36% | 51° | 84° | 22° |
| February | 6.4 in | 12 | 65% | 56% | 50° | 83° | 23° |
| March | 4.3 in | 12 | 67% | 50% | 49° | 92° | 28° |
| April | 2.0 in | 8 | 60% | 63% | 48° | 98° | 30° |
| May | 1.3 in | 5 | 56% | 72% | 48° | 101° | 32° |
| June | 0.29 in | 1 | 52% | 75% | 49° | 108° | 34° |
| July | 0.01 in | 0 | 52% | 87% | 50° | 110° | 42° |
| August | 0.04 in | 0 | 54% | 83% | 52° | 107° | 30° |
| September | 0.15 in | 1 | 56% | 79% | 53° | 115° | 37° |
| October | 1.6 in | 4 | 53% | 70% | 52° | 105° | 30° |
| November | 3.3 in | 9 | 66% | 56% | 52° | 88° | 25° |
| December | 6.5 in | 13 | 78% | 35% | 52° | 78° | 16° |
From ERA5 reanalysis. Sunshine is estimated from cloud cover.
Santa Rosa climate questions
How much rain does Santa Rosa get?
Santa Rosa gets 31.5 in of precipitation in an average year, over about 79 rainy days.
What is the wettest month in Santa Rosa?
December is the wettest month in Santa Rosa, with 6.5 in. July is the driest, with 0.0 in.
How many rainy days does Santa Rosa have a year?
Santa Rosa has about 79 days with measurable rain in an average year. January has the most, about 14.
What is the hottest month in Santa Rosa?
August is the warmest month in Santa Rosa, with an average high of 83°F.
What is the coldest month in Santa Rosa?
December is the coldest month in Santa Rosa, with an average low of 39°F.
What is the record high temperature in Santa Rosa?
The record high at the Santa Rosa station is 115°F, set on September 6, 2022. The record low is 16°F, on December 9, 1972.
What is the sunniest month in Santa Rosa?
July is the sunniest month in Santa Rosa, with sunshine about 87% of daylight hours. December is the cloudiest.
When is the first frost in Santa Rosa?
The first fall freeze in Santa Rosa typically comes around November 27. The last spring freeze is around February 20.
What is the best time to visit Santa Rosa?
The most comfortable time to visit is typically February to June and October to November, when daytime highs sit near 70°F.
Source: NOAA GHCN-Daily station SANTA ROSA (2 km away).
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Normals from NOAA GHCN-Daily station SANTA ROSA.