Photo: Wulfnoth of English Wikipedia · CC BY 3.0Santa Rosa’s winters are milder and less snowy than most of the U.S.
A typical July afternoon reaches 84°, a January night drops to 38°, and snow is almost unheard of.
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 California 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 279 frost-free days a year
In half of years the last 32° night comes by February 25 and the first by December 1. Frost and day counts come from NOAA’s station at Santa Rosa, CA, 0.8 miles from the city’s center point, at about the same height.
The 2023 USDA map puts Santa Rosa’s center in zone 9b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 25°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 32 inches of rain a year
December is the wettest month and July the driest. Rain falls on about 81 days a year. Snow is rare: about 0.0" in a normal year at Santa Rosa, CA, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Santa Rosa
86% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from November through March.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Santa Rosa, CA.
Living with Santa Rosa’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
279 frost-free days in zone 9b. The last frost comes by Feb 25 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Dec 1.
Months with highs of 62–84° and lows of 40° or more: March, April, May, June, July, September, October and November. 69 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Santa Rosa from natural hazards, earthquakes are the largest share (58%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Santa Rosa and its neighbors
Every town next door is within a degree of Santa Rosa in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Santa Rosa’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Santa Rosa, CA | 38° | 84° | 32" | 0.0" |
| Winston, OR | 37° | 86° | 33" | 0.0" |
| Felida, WA | 35° | 81° | 42" | 0.8" |
| Kill Devil Hills, NC | 35° | 86° | 50" | 1.1" |
| Rockport, TX | 48° | 91° | 35" | 0.3" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
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°).
A bigger shift than in 58% 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. In a city of 179,000 people, part of the change is the city itself: pavement and buildings hold heat (the urban heat island).
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 California’s.
Santa Rosa weather by month
Highs, lows and precipitation from NOAA’s grid at Santa Rosa’s center; snow, wet days and snow on the ground from Santa Rosa, CA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 58° | 38° | 6.1" | 0.0" | 14 | 0 | 45° – 52° |
| February | 62° | 40° | 6.2" | 0.0" | 13 | 0 | 46° – 56° |
| March | 65° | 41° | 4.5" | 0.0" | 12 | 0 | 47° – 59° |
| April | 69° | 43° | 2.1" | 0.0" | 8 | 0 | 51° – 60° |
| May | 75° | 46° | 1.2" | 0.0" | 5 | 0 | 56° – 66° |
| June | 81° | 50° | 0.3" | 0.0" | 1 | 0 | 62° – 68° |
| July | 84° | 51° | 0.0" | 0.0" | 0 | 0 | 65° – 70° |
| August | 84° | 51° | 0.0" | 0.0" | 0 | 0 | 65° – 72° |
| September | 84° | 50° | 0.1" | 0.0" | 1 | 0 | 63° – 70° |
| October | 77° | 46° | 1.6" | 0.0" | 4 | 0 | 59° – 67° |
| November | 65° | 41° | 3.4" | 0.0" | 9 | 0 | 47° – 57° |
| December | 58° | 37° | 6.7" | 0.0" | 13 | 0 | 44° – 52° |
| Year | 72° | 44° | 32.1" | 0.0" | 81 | 0 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 47° to 59°. July is the most reliable, staying within 6°.
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.
- Snow: Santa Rosa, CA (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Santa Rosa, CA, 0.8 miles from the city’s center point, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- 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 84°, a January night drops to 38°, and snow is almost unheard of. Milder January nights than 85% of U.S. towns; cooler July afternoons than 63% of U.S. towns.
How cold does it get in Santa Rosa in winter?
December nights average 37°. About 15 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 44°.
How much snow does Santa Rosa get?
About 0.0 inches in a normal winter at Santa Rosa, CA, so most winters see none.
How hot does it get in Santa Rosa?
July, with a typical high of 84° and a low of 51°. About 26 days a year reach 90° and 2 reach 100° (Santa Rosa, CA).
When is the first and last frost in Santa Rosa?
In half of years the last spring frost (32°) comes by February 25 and the first fall frost by December 1, about 279 frost-free days, at Santa Rosa, CA.
What growing zone is Santa Rosa in?
Zone 9b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 25°.
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), March, April, May, June, July, September, October 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 1.5° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 58% 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.