Santa Rosa has some of the warmest summer afternoons among U.S. towns
On a normal January night the air cools to about 39°. It is a dry place: less rain and snow fall here than on 98% of U.S. towns. Warming shows here too: 2.0° more than in 1901–2000, led by March. Picnics, hikes and garden evenings suit February, March and November, with highs of 71–77°.
A year in Santa Rosa at a glance
Each month’s typical high and low, and what it brings.
What stands out about Santa Rosa’s climate
Compared with towns across the U.S., with Santa Rosa’s place in Arizona beside it.
What a year in Santa Rosa feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 9 inches of rain a year
August is the wettest month and May the driest.
Rain + melted snow by month
Inches of water
Living with Santa Rosa’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 9a.
Months with highs of 62–84° and lows of 40° or more: February, March and November. 11 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Santa Rosa from natural hazards, river flooding is the largest share (69%); heat waves, cold waves, winter storms and ice storms together are 27%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Santa Rosa and similar climates
TownRatings has no climate map of the towns around Santa Rosa yet.
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Santa Rosa averaged 2.0° warmer than the 1900s. The biggest change is in March (+2.8°).
A bigger shift than in 88% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Santa Rosa compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Santa Rosa’s place among Arizona’s.
Santa Rosa weather by month
Highs, lows and precipitation from NOAA’s grid at Santa Rosa’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 68° | 39° | 0.9" | 49° – 58° |
| February | 71° | 41° | 0.9" | 50° – 62° |
| March | 77° | 46° | 0.7" | 54° – 68° |
| April | 84° | 52° | 0.2" | 61° – 73° |
| May | 93° | 59° | 0.1" | 70° – 81° |
| June | 103° | 68° | 0.2" | 80° – 89° |
| July | 103° | 75° | 1.4" | 86° – 92° |
| August | 102° | 73° | 2.0" | 85° – 92° |
| September | 98° | 68° | 0.9" | 78° – 86° |
| October | 88° | 56° | 0.5" | 69° – 77° |
| November | 76° | 45° | 0.6" | 53° – 67° |
| December | 66° | 38° | 0.9" | 48° – 56° |
| Year | 86° | 55° | 9.1" |
How much a month can swing
A normal is an average. November swings the most: from 1991 to 2020 its average ranged from 53° to 67°. July is the most reliable, staying within 5°.
Where Santa Rosa’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Santa Rosa’s center.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Santa Rosa’s climate
What is the weather like in Santa Rosa?
A typical July afternoon reaches 103°, a January night drops to 39°. Milder January nights than 86% of U.S. towns; hotter July afternoons than all but 87 U.S. towns.
How cold does it get in Santa Rosa in winter?
December nights average 38°. In the coldest December of the last 30 years the month averaged 48°.
How hot does it get in Santa Rosa?
July, with a typical high of 103°. 90° days are rare.
What growing zone is Santa Rosa in?
Zone 9a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 21°.
What is the best time of year to visit Santa Rosa?
By one simple rule (highs of 62–84° and lows of 40° or more), February, March and November. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Santa Rosa getting warmer?
Yes: 1991–2020 averaged 2.0° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 88% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Santa Rosa.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.