Santa Rosa, California Weather
Coastal fog thickens at dawn. Day 76 of spring. Read this microseason across nine climate regions →
Santa Rosa weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Foggy——89°51°—
- ThursdayJun 4Clear——89°54°0°
- FridayJun 5Overcast——93°59°+4°
- SaturdayJun 6Overcast——86°53°-7°
- SundayJun 7Overcast——83°50°-3°
- MondayJun 8Overcast12%—86°55°+3°
- TuesdayJun 9Overcast——79°56°-7°
Ozone at AQI 36 — peak already passed at 1 PM under clear skies. AQI flat over the last 6 hours (within ±3 points). Levels should ease through evening.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 36 — peak already passed at 1 PM under clear skies. Levels should ease through evening.
- Present
- AQI 36
- UV peak
- 5.0 at earlier today
- Sky at peak
- clear
- Projected peak
- AQI 36
PM × Wind × Precip
PM2.5/PM10 ratio 0.69 with 15 mph wind — characteristic of long-range haze transport rather than a local source.
- PM2.5/PM10
- 0.69
- Wind
- breezy
- Recent rain
- 0h in last 6h
- Pattern
- transport
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
The higher the clouds, the finer the weather.
- Moonrise
- 6:00 AM
- Moonset
- 3:20 PM
- In sign
- ♑︎ Capricorn
Coastal fog thickens at dawn
Santa Rosa at a glance
- Today vs. normal: 11°F above the seasonal normal for this latitude
- Last frost: April 7 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Peak growing season
As of June 3, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | — | — |
| April | lettuce, peas, spinach, radishes | — |
| May | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
August brings Santa Rosa's warmest temperatures (~68°F mean) while December delivers the coldest (~49°F). December also brings peak rainfall at 6.5 inches, contrasting sharply with July's 0.0 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 49° | 5.8″ | 9 |
| February | 52° | 6.4″ | 9 |
| March | 54° | 4.3″ | 8 |
| April | 57° | 2.0″ | 5 |
| May | 61° | 1.3″ | 3 |
| June | 66° | 0.3″ | 1 |
| July | 67° | 0.0″ | 0 |
| August | 68° | 0.0″ | 0 |
| September | 68° | 0.1″ | 0 |
| October | 63° | 1.6″ | 2 |
| November | 55° | 3.3″ | 5 |
| December | 49° | 6.5″ | 9 |
Regional context
Santa Rosa falls within a hot-summer Mediterranean climate region. Cities throughout this area experience similar temperature ranges, seasonal patterns, and growing conditions.
Similar climates: Los Angeles, CA, San Francisco, CA, San Diego, CA, Riverside, CA, Sacramento, CA.
Naturalist notes
Oak trees complete their leaf emergence by late May, creating full canopies across the local hillsides.
Western bluebirds begin their second nesting cycle in June, taking advantage of the abundant insect activity.
Frequently asked
- When does it freeze in Santa Rosa?
- The last spring frost in Santa Rosa typically occurs around mid-April, while the first fall frost returns around mid-November.
- What is the rainy season in Santa Rosa?
- December brings the heaviest rainfall with about 6.5 inches on average. The city receives roughly 32 inches annually.
- What is the warmest month in Santa Rosa?
- August records the highest temperatures, averaging about 68°F.
- What is the coldest month in Santa Rosa?
- December shows the lowest temperatures, averaging about 49°F.
- When can I start a vegetable garden in Santa Rosa?
- Cool-season crops like peas and lettuce can be planted around the last spring frost in mid-April. Warm-season crops such as tomatoes and peppers should wait 1–2 weeks after.
- How many rainy days does Santa Rosa get?
- Santa Rosa experiences about 52 rainy days per year on average.
- What hardiness zone is Santa Rosa?
- Santa Rosa's USDA hardiness zone depends on its lowest average winter temperature. Use the USDA's online lookup tool with the city ZIP code for the current zone designation.
Climate
Santa Rosa, California experiences a hot-summer Mediterranean climate. January temperatures hover near 49°F while July averages 67°F, creating an 18°F seasonal swing.
Annual precipitation totals about 32 inches across roughly 52 rainy days throughout the year.
Weather patterns here follow the influence of latitude (38.4°N), proximity to large water bodies, and elevation. These factors determine what grows in the area, when frost occurs, and the daily weather characteristics.