Riverside, California Weather
Coastal fog thickens at dawn. Day 77 of spring. Read this microseason across nine climate regions →
Riverside weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Foggy——89°57°—
- ThursdayJun 4Foggy——93°58°+4°
- FridayJun 5Overcast——91°56°-2°
- SaturdayJun 6Overcast——88°68°-3°
- SundayJun 7Clear——86°64°-2°
- MondayJun 8Clear——89°66°+3°
- TuesdayJun 9Clear——89°68°0°
Ozone at AQI 81 now. AQI up 47 in the last 6 hours — air quality is degrading. With UV 0.0 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 19 by mid-afternoon.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion during the projected peak around 6 AM.
What's driving it
Ozone × UV × Sky
Ozone at AQI 81 now. With UV 0.0 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 19 by mid-afternoon.
- Present
- AQI 81
- UV peak
- 0.0 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 19
PM × Wind × Precip
PM2.5 at 18.0 µg/m³ (AQI 68) with a 0.70 fine-to-coarse ratio and 2 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.70
- Wind
- calm
- Recent rain
- 0h in last 6h
- Pattern
- stagnant smoke
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).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 6:03 AM
- Moonset
- 4:13 PM
- In sign
- ♑︎ Capricorn
Coastal fog thickens at dawn
Riverside at a glance
- Today vs. normal: 13°F below the seasonal normal for this latitude
- Last frost: March 11 (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 4, 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 | lettuce, peas, spinach, radishes | — |
| April | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | — |
| May | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | — | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | — | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | fall brassicas, garlic (overwinter), carrots | — |
| December | — | — |
A year in weather
August brings Riverside's warmest temperatures (~81°F mean) while December delivers the coldest (~56°F). February sees peak rainfall at 2.5 inches, then precipitation drops to just 0.1 inches in June.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 56° | 2.2″ | 4 |
| February | 57° | 2.5″ | 5 |
| March | 60° | 1.6″ | 3 |
| April | 64° | 0.6″ | 1 |
| May | 68° | 0.2″ | 1 |
| June | 74° | 0.1″ | 0 |
| July | 80° | 0.1″ | 0 |
| August | 81° | 0.1″ | 0 |
| September | 77° | 0.1″ | 0 |
| October | 69° | 0.4″ | 1 |
| November | 61° | 0.7″ | 2 |
| December | 56° | 1.4″ | 3 |
Regional context
Riverside belongs to a hot-summer Mediterranean climate region that encompasses nearby cities with similar temperature ranges, seasonal patterns, and growing conditions.
Similar climates: Los Angeles, CA, San Francisco, CA, San Diego, CA, Sacramento, CA, San Jose, CA.
Naturalist notes
Late May brings the sweet fragrance of California orange blossoms across Riverside's citrus groves.
House finches begin their second nesting cycle around mid-June as summer heat settles over the valley.
Frequently asked
- When does it freeze in Riverside?
- Riverside's last spring frost typically occurs around mid-March, and the first fall frost arrives around mid-December.
- What is the rainy season in Riverside?
- February brings the most rainfall with about 2.5 inches on average; the city receives roughly 10 inches annually.
- What is the warmest month in Riverside?
- August typically records the warmest temperatures, averaging about 81°F.
- What is the coldest month in Riverside?
- December typically brings the coldest temperatures, averaging about 56°F.
- When can I start a vegetable garden in Riverside?
- Cool-season crops (peas, lettuce) can be planted around the last spring frost (mid-March); warm-season crops (tomatoes, peppers) should wait until 1–2 weeks after.
- How many rainy days does Riverside get?
- Riverside averages about 19 rainy days per year.
- What hardiness zone is Riverside?
- Riverside's USDA hardiness zone depends on its lowest average winter temperature; check the USDA's online lookup with the city ZIP for the current zone designation.
Climate
Riverside, California experiences a hot-summer Mediterranean climate zone. January temperatures hover near 56°F while July averages 80°F — a 23°F seasonal swing.
Throughout the year, Riverside receives about 10 inches of precipitation spread over roughly 19 rainy days.
Geography shapes Riverside's weather patterns through its latitude (33.9°N), proximity to large water bodies, and elevation. These factors determine what grows here, when frost is likely, and the daily weather patterns.