Frost dates for 92503 — Riverside, CA
Frost is light and occasional here — typically a few cold nights around midwinter (about 4 a year). Cover tender plants when frost is forecast.
How Riverside compares
- In a typical year, frost nights in Riverside fall between December 30 and January 9. In 1 year in 10 the first frost comes as early as December 5, or the last frost as late as February 21.
- Nearby Anaheim, CA, 42 km away, rarely gets frost, a reminder of how much elevation and distance from the coast matter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | December 16 |
| 50% (median) | January 9 |
| 10% (safe for tender plants) | February 21 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | December 5 |
| 50% (median) | December 30 |
| 90% (late) | February 6 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Gardening where frost is rare
Riverside, CA only freezes on a few winter nights, so the usual "plant after the last frost" rule doesn't apply. Heat and rainfall decide the seasons instead:
- Cool-season crops (lettuce, broccoli, peas, carrots) grow best from fall through late winter.
- Warm-season crops (tomatoes, peppers, beans, squash) do best planted in late winter to spring, and again in late summer for a fall crop — midsummer heat can stop tomatoes setting fruit.
- Heat lovers (okra, sweet potatoes, melons) can be planted through spring and early summer.
About these dates
Based on 1991–2020 NOAA climate normals for the Riverside Muni Ap, CA weather station, 4 km away (elevation 804 ft (245 m)).
ZIP codes in Riverside: 92501 92502 92503 92504 92505 92506 92507 92508 92509 92513 92514 92515 92516 92517 92519 92521 92522
Frost dates near Riverside
- March Air Reserve Base Jan 9 · Dec 25
- Norco Jan 17 · Dec 19
- Mira Loma Jan 9 · Dec 30
- Corona Jan 9 · Dec 30
- Bloomington Jan 10 · Jan 2
- Grand Terrace Jan 10 · Jan 2
- Fontana Jan 4 · Dec 30
- Guasti Jan 4 · Dec 30
Frequently asked questions
When is the last frost in Riverside, CA?
The median last spring frost in Riverside, CA is January 9. There is still about a 10% chance of frost after February 21, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Riverside, CA?
The median first fall frost is December 30, with about a 10% chance of frost before December 5.
How long is the growing season in Riverside, CA?
About 355 days between the median last spring frost and first fall frost.
What planting zone is Riverside, CA?
Riverside, CA is in USDA hardiness zone 10a.