Weather in Riverside, California
Fog and sun in daily rhythm. Day 59 of spring. Read this microseason across nine climate regions →
- TodayMay 16Overcast—76°59°
- SundayMay 17Overcast—78°56°
- MondayMay 18Overcast—85°53°
- TuesdayMay 19Overcast—90°62°
- WednesdayMay 20Overcast—88°65°
- ThursdayMay 21Overcast—86°64°
- FridayMay 22Clear—86°65°
- PM 2.5
- 10.8 μg/m³
- PM 10
- 17.5 μg/m³
- NO₂
- 3.3 μg/m³
- Ozone
- 98.0 μg/m³
- UV Index
- 0.0 Low
When the dew is on the grass, rain will never come to pass.
- Moonrise
- 1:03 PM
- Moonset
- 3:14 AM
- In sign
- ♊︎ Gemini
Fog and sun in daily rhythm
Riverside at a glance
- Today vs. normal: 15°F below the seasonal normal for this latitude
- Last frost: March 11 (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
Peak growing season
As of May 17, 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.