Santa Rosa climate
Santa Rosa is warmest in July, with average highs of 30 °C, and coldest in January, when nights average 4.5 °C. December is the wettest month (150 mm) and July the driest (0.3 mm). Figures are 1991–2020 climate normals.
Across a full year Santa Rosa averages 753 mm of rain, 141 days above 25 °C and 7 days below freezing.
United States · 50 m elevation · population 178,127 · 1991–2020 normals
Temperature below 0 °C to above 30 °C Rain band height is that month’s share of the wettest month
- Warmest month July 30 °C
- Coldest month January 4.5 °C
- Driest month July 0 mm
- Wettest month December 150 mm
- Least cloud July 16 % cloud
- Hottest on record September 44 °C
- Coldest on record January -3.1 °C
What to expectSanta Rosa through the year
Santa Rosa has a clear annual cycle: average daily highs run from 15 °C in January to 30 °C in July, a swing of 12 °C in mean temperature across the year.
Counted across a normal year, 141 days a year reach 25 °C, 60 of them reach 30 °C, 7 nights drop below freezing. The warmest reading in the 1991–2020 record is 44 °C, in September.
Rain is strongly seasonal. December averages 150 mm against 0 mm in July — 463 times as much. Planning around the dry months matters more here than planning around temperature.
Month by month
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| January | 14.8 °C | 146 mm | 62 % |
| February | 16.2 °C | 148 mm | 60 % |
| March | 18.0 °C | 111 mm | 57 % |
| April | 20.4 °C | 50 mm | 47 % |
| May | 24.1 °C | 28 mm | 39 % |
| June | 28.3 °C | 7 mm | 25 % |
| July | 29.9 °C | under 1 mm | 16 % |
| August | 29.9 °C | 1 mm | 17 % |
| September | 28.9 °C | 3 mm | 19 % |
| October | 24.9 °C | 33 mm | 33 % |
| November | 18.5 °C | 75 mm | 50 % |
| December | 14.5 °C | 150 mm | 59 % |
Temperature month by month
| Month | Avg high | Avg low | Mean | Record high | Record low | Days above 25 °C | Days above 30 °C | Days below 0 °C |
|---|---|---|---|---|---|---|---|---|
| January | 14.8 °C | 4.5 °C | 8.8 °C | 24.6 °C | -3.1 °C | 0 | 0 | 3 |
| February | 16.2 °C | 5.3 °C | 10.0 °C | 26.1 °C | -2.3 °C | 0 | 0 | 1 |
| March | 18.0 °C | 6.6 °C | 11.6 °C | 29.5 °C | -2.5 °C | 2 | 0 | 0 |
| April | 20.4 °C | 7.9 °C | 13.4 °C | 33.5 °C | 0.7 °C | 5 | 1 | 0 |
| May | 24.1 °C | 10.6 °C | 16.6 °C | 39.1 °C | 3.9 °C | 13 | 4 | 0 |
| June | 28.3 °C | 13.0 °C | 19.9 °C | 42.8 °C | 7.3 °C | 23 | 11 | 0 |
| July | 29.9 °C | 14.0 °C | 21.0 °C | 40.9 °C | 9.4 °C | 29 | 15 | 0 |
| August | 29.9 °C | 14.2 °C | 20.9 °C | 41.4 °C | 10.8 °C | 29 | 14 | 0 |
| September | 28.9 °C | 13.6 °C | 20.0 °C | 43.7 °C | 7.7 °C | 25 | 12 | 0 |
| October | 24.9 °C | 11.2 °C | 17.0 °C | 40.2 °C | 4.5 °C | 15 | 4 | 0 |
| November | 18.5 °C | 7.3 °C | 12.1 °C | 30.6 °C | -1.7 °C | 2 | 0 | 0 |
| December | 14.5 °C | 4.7 °C | 8.8 °C | 23.6 °C | -2.9 °C | 0 | 0 | 3 |
Rain, sun and wind month by month
| Month | Rainfall | Wet days | Daylight | Cloud cover | Humidity | Wind |
|---|---|---|---|---|---|---|
| January | 146 mm | 10 | 9.8 h/day | 62 % | 82 % | 11 km/h |
| February | 148 mm | 10 | 11 h/day | 60 % | 79 % | 13 km/h |
| March | 111 mm | 9 | 12 h/day | 57 % | 77 % | 14 km/h |
| April | 50 mm | 6 | 13 h/day | 47 % | 71 % | 15 km/h |
| May | 28 mm | 4 | 14 h/day | 39 % | 65 % | 15 km/h |
| June | 7 mm | 1 | 15 h/day | 25 % | 58 % | 15 km/h |
| July | under 1 mm | 0 | 15 h/day | 16 % | 60 % | 13 km/h |
| August | 1 mm | 0 | 14 h/day | 17 % | 62 % | 13 km/h |
| September | 3 mm | 1 | 12 h/day | 19 % | 62 % | 12 km/h |
| October | 33 mm | 3 | 11 h/day | 33 % | 64 % | 12 km/h |
| November | 75 mm | 6 | 10 h/day | 50 % | 75 % | 11 km/h |
| December | 150 mm | 10 | 9.5 h/day | 59 % | 80 % | 12 km/h |
Where Santa Rosa ranks
| Ranking | Position | Value |
|---|---|---|
| The driest places in North America in July | 3rdof 50 | 0.3 mm |
| Places with the best weather in North America in May | 12thof 50 | 95/100 |
| The driest places in North America in September | 15thof 50 | 3.3 mm |
| Places with the best weather in North America in October | 21stof 50 | 94/100 |
| The driest places in North America in August | 21stof 50 | 1.1 mm |
| Places with the best weather in North America in June | 37thof 50 | 87/100 |
Planning a trip? See the best time to visit Santa Rosa.
QuestionsCommon questions about Santa Rosa’s climate
When is the best time to visit Santa Rosa?
That depends on what you want, so the honest answer is a comparison rather than a single month. June, August, September sit closest to 20 °C on average, July is the warmest month and July the driest. The month-by-month table above has the full picture.
How hot does Santa Rosa get?
In July, the warmest month, daily highs average 30 °C. About 60 days a year pass 30 °C. The highest value in the 1991–2020 record is 44 °C.
How cold does it get in winter?
Nights average 4.5 °C in January, the coldest month. A normal year has 7 nights below freezing.
Which month is wettest in Santa Rosa?
December, averaging 150 mm over 10 days with rain. The driest month is July with 0 mm. The year as a whole averages 753 mm.
Are these figures a forecast?
No. They are 1991–2020 climate normals: the average of thirty years, which describes what a month is usually like in Santa Rosa rather than what any particular week will bring. Individual years can differ substantially from the normal.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: monthly rankings, daylight hours, beach and comfort scores. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.