Lake Forest, CA frost dates
Frost is light and occasional here — typically a few cold nights around midwinter (about 2 a year). Cover tender plants when frost is forecast.
How Lake Forest compares
- In a typical year, frost nights in Lake Forest fall between December 25 and January 5. In 1 year in 10 the first frost comes as early as December 3, or the last frost as late as February 2.
- Nearby Mission Viejo, CA, 5 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 14 |
| 50% (median) | January 5 |
| 10% (safe for tender plants) | February 2 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | December 3 |
| 50% (median) | December 25 |
| 90% (late) | January 20 |
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
Lake Forest, 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 Tustin Irvine Rch, CA weather station, 9 km away (elevation 236 ft (72 m)).
Frost dates near Lake Forest
- El Toro Jan 5 · Dec 25
- Foothill Ranch rare frost
- Mission Viejo rare frost
- Laguna Woods Jan 6 · Jan 2
- Laguna Hills Jan 6 · Jan 2
- East Irvine Jan 5 · Dec 25
- Aliso Viejo Jan 6 · Jan 2
- Rancho Santa Margarita rare frost
- Trabuco Canyon rare frost
- Irvine Jan 5 · Dec 25
Frequently asked questions
When is the last frost in Lake Forest, CA?
The median last spring frost in Lake Forest, CA is January 5. There is still about a 10% chance of frost after February 2, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Lake Forest, CA?
The median first fall frost is December 25, with about a 10% chance of frost before December 3.
How long is the growing season in Lake Forest, CA?
About 354 days between the median last spring frost and first fall frost.
What planting zone is Lake Forest, CA?
Lake Forest, CA is in USDA hardiness zone 10b.