Frost dates for 92337 — Fontana, 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 Fontana compares
- In a typical year, frost nights in Fontana 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.
- Compared with Riverside, CA, 13 km away, the last frost here is the same as there.
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
Fontana, 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, 11 km away (elevation 804 ft (245 m)).
ZIP codes in Fontana: 92331 92334 92335 92336 92337
Frost dates near Fontana
- Bloomington Jan 10 · Jan 2
- Mira Loma Jan 9 · Dec 30
- Guasti Jan 4 · Dec 30
- Rialto Jan 10 · Jan 2
- March Air Reserve Base Jan 9 · Dec 25
- Riverside Jan 9 · Dec 25
- Rancho Cucamonga Jan 4 · Dec 30
- Grand Terrace Jan 10 · Jan 2
Frequently asked questions
When is the last frost in Fontana, CA?
The median last spring frost in Fontana, 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 Fontana, 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 Fontana, CA?
About 355 days between the median last spring frost and first fall frost.
What planting zone is Fontana, CA?
Fontana, CA is in USDA hardiness zone 10a.