Riverside, California Weather
Ceanothus blooms again. Day 93 of summer. Read this microseason across nine climate regions →
Riverside weather forecast — hour by hour, 7-day outlook, NOAA radar
Conditions updated 12:20 AM PDT · Open-Meteo
- TodaySep 21Clear——82°64°—
- TuesdaySep 22Overcast——85°62°+3°
- WednesdaySep 23Clear——93°72°+8°
- ThursdaySep 24Clear——93°74°0°
- FridaySep 25Clear——96°75°+3°
- SaturdaySep 26Overcast——97°78°+1°
- SundaySep 27Overcast——95°79°-2°
Air quality now AQI 61 · Moderate
AQI 61 (Moderate), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 15.4 µg/m³ (AQI 63) with a 0.83 fine-to-coarse ratio and 4 mph wind — combustion smoke trapped in stagnant air, not road dust.
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 31 now. With UV 3.3 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 14.
- Present
- AQI 31
- UV peak
- 3.3 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 14
PM × Wind × Precip
PM2.5 at 15.4 µg/m³ (AQI 63) with a 0.83 fine-to-coarse ratio and 4 mph wind — combustion smoke trapped in stagnant air, not road dust.
- PM2.5/PM10
- 0.83
- 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).
September dries up ditches or breaks down bridges.
- Moonrise
- 4:08 PM
- Moonset
- 1:33 AM
- In sign
- ♑︎ Capricorn
Ceanothus blooms again
Read this microseason across nine climate regions →
All 72 microseasons on the year wheel →
Riverside at a glance
- Today vs. normal: Today averages 73°F (high 82°F, low 64°F), 2°F below the 75°F normal for Sep 21
- Last frost: January 9 (1991–2020 median, NOAA station 2 km away)
- Microseason: Sep 21–25
- Planting calendar: September — plant tomatoes, peppers, beans, squash; harvest tomatoes, peppers, beans, summer squash, winter squash
15-Day Forecast — Riverside
- Mon82°61°1%
- Tue85°62°0%
- Wed93°72°0%
- Thu93°74°3%
- Fri96°75°1%
- Sat97°78°1%
- Sun95°79°4%
- Mon100°82°9%
- Tue99°86°15%
- Wed90°76°13%
- Thu78°72°4%
- Fri93°72°6%
- Sat95°79°13%
- Sun100°80°12%
- Mon87°75°3%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near Riverside
Interactive wind and temperature map centered on Riverside — it loads in your browser. Open the full weather map.
Right now in the garden
Peak growing season
As of September 21, the growing season is at its peak — the first frost (around December 25) is weeks away. Fall transplants go in about 10–12 weeks before the first frost, October 2 to October 16 here. This city's planting calendar for September: plant tomatoes, peppers, beans, and squash; harvest tomatoes, peppers, beans, summer squash, and winter squash.
Sun & seasons in Riverside
Riverside sits in Riverside County, where the year’s longest day runs 14h 25m of daylight and its shortest just 9h 53m — a swing of +4h 31m between the June and December solstices. Clocks spring forward on Sunday, March 8, 2026 and fall back on Sunday, November 1, 2026.
Los Angeles, the state’s largest city, lies about 59 miles to the WNW. The nearest town Riverside tracks is Moreno Valley, roughly 11 miles to the E.
Air quality in Riverside
Air quality in Riverside’s county has trended cleaner since 2020; its cleanest year on record was 2022 (median AQI 77). See the full air-quality history for Riverside.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | lettuce, peas, spinach, radishes | spinach, radishes, fall brassicas, carrots |
| February | — | lettuce, peas, spinach, radishes |
| March | — | lettuce, peas, spinach |
| April | tomatoes, peppers, beans, squash | peas |
| May | tomatoes, peppers, beans, squash | summer squash, garlic |
| June | beans, squash | tomatoes, peppers, beans, summer squash |
| July | beans, squash | tomatoes, peppers, beans, summer squash, winter squash |
| August | tomatoes, peppers, beans, squash | tomatoes, peppers, beans, summer squash, winter squash |
| September | tomatoes, peppers, beans, squash | tomatoes, peppers, beans, summer squash, winter squash |
| October | beans, squash, fall brassicas, carrots | beans, summer squash, winter squash |
| November | garlic (overwinter) | tomatoes, peppers, beans, summer squash, winter squash |
| December | lettuce, peas, spinach, radishes, garlic (overwinter) | tomatoes, peppers, beans, summer squash, winter squash, fall brassicas, carrots |
A year in weather
Riverside peaks at about 80°F in August and bottoms near 52°F in January; February brings the heaviest rain (3.4 inches) and August the least (0.0 inches).
| Month | Mean temp | Precip |
|---|---|---|
| January | 52° | 3.3″ |
| February | 54° | 3.4″ |
| March | 57° | 3.0″ |
| April | 62° | 1.5″ |
| May | 67° | 0.5″ |
| June | 73° | 0.1″ |
| July | 79° | 0.1″ |
| August | 80° | 0.0″ |
| September | 76° | 0.1″ |
| October | 69° | 0.5″ |
| November | 59° | 1.6″ |
| December | 53° | 2.6″ |
Regional context
Similar climates Woodcrest, CA, El Sobrante, CA, Jurupa Valley, CA
Drawing on modelled 1991-2020 normals (EC_Earth3P_HR model via Open-Meteo), Riverside's January averages 52°F and July 79°F — 27°F apart — while precipitation totals roughly 16.7 inches.
Precipitation in Riverside peaks in the cool season: February averages 3.4 inches, while August bottoms out at 0.0 inches. That groups Riverside with places like Woodcrest, CA, El Sobrante, CA and Jurupa Valley, CA on the same cool-season storm track.
The cool-season window in Riverside starts at January 9, when nights stop freezing — think lettuce, chard, arugula, and mustard greens. Warm-soil crops in Riverside wait about two weeks past Riverside's last frost, once the soil warms. Riverside's window closes around December 25 as Riverside's overnight lows return below freezing. In about half of years, Riverside's last freeze comes after January 9.
Similar climates: Woodcrest, CA, El Sobrante, CA, Jurupa Valley, CA, Highgrove, CA, March ARB, CA.
Frequently asked
- When does it freeze in Riverside?
- Riverside's last spring frost lands near January 9, and in Riverside the first fall frost follows around December 25.
- What is the rainy season in Riverside?
- Riverside sees its heaviest rain in February (around 3.4 inches), part of roughly 17 inches a year.
- What is the warmest month in Riverside?
- On average August tops the year in Riverside at about 80°F.
- What is the coldest month in Riverside?
- The coldest stretch in Riverside falls in January, around 52°F on average.
- When can I start a vegetable garden in Riverside?
- In Riverside, sow peas and hardy greens around January 9; Riverside's tomatoes and peppers wait two weeks more.
- What hardiness zone is Riverside?
- With January around 52°F, Riverside's zone reflects that minimum — the USDA ZIP map confirms Riverside's band.
- What is the 10-day forecast for Riverside?
- Riverside's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
- Will it rain this week in Riverside?
- See this week's day-by-day rain chances for Riverside in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Riverside?
- Current conditions for Riverside and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Riverside forecast updated?
- The Riverside forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Riverside?
- Today's sunrise and sunset times for Riverside are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
- How accurate is the weather forecast for Riverside?
- The next few days in Riverside's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Riverside sits at 33.9°N; its climate zone is hot-summer Mediterranean (Köppen approximation).
ZIP codes in Riverside
- 92501
- 92502
- 92503
- 92504
- 92505
- 92506
- 92507
- 92508
- 92513
- 92514
- 92516
- 92517
- 92521
- 92522