Weather in Santa Rosa, California
Fog and sun in daily rhythm. Day 58 of spring. Read this microseason across nine climate regions →
- TodayMay 16Overcast—79°50°
- SundayMay 17Overcast—74°48°
- MondayMay 18Mostly Clear—86°55°
- TuesdayMay 19Partly Cloudy—89°60°
- WednesdayMay 20Overcast—89°59°
- ThursdayMay 21Overcast—87°58°
- FridayMay 22Overcast—79°53°
- PM 2.5
- 6.1 μg/m³
- PM 10
- 9.5 μg/m³
- NO₂
- 0.4 μg/m³
- Ozone
- 82.0 μg/m³
- UV Index
- 4.2 Moderate
Flowers blooming in late autumn, a sure sign of a bad winter coming.
- Moonrise
- 12:25 PM
- Moonset
- 2:35 AM
- In sign
- ♉︎ Taurus
Fog and sun in daily rhythm
Santa Rosa at a glance
- Today vs. normal: 3°F above the seasonal normal for this latitude
- Last frost: April 7 (climatological average for this latitude)
- Microseason: 28 of 72, May 16–20
- Planting window: Direct sow okra, melons, and southern peas. Thin carrot rows.
Right now in the garden
Warm-season window is open
As of May 16, the last spring frost has passed for most years. Transplant tomatoes, peppers, eggplants, basil, and cucurbits (cucumbers, squash, melons) now. Direct-sow beans and corn into warm soil.
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.