Los Alamos, CA frost dates
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 Los Alamos compares
- In a typical year, frost nights in Los Alamos fall between December 19 and January 20. In 1 year in 10 the first frost comes as early as November 27, or the last frost as late as February 24.
- Compared with Santa Maria, CA, 30 km away, the last frost here is 15 days earlier than there.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | December 16 |
| 50% (median) | January 20 |
| 10% (safe for tender plants) | February 24 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | November 27 |
| 50% (median) | December 19 |
| 90% (late) | January 26 |
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
Los Alamos, 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 Lompoc, CA weather station, 25 km away (elevation 75 ft (23 m)).
Frost dates near Los Alamos
- Solvang Apr 11 · Nov 8
- Los Olivos Apr 11 · Nov 8
- Buellton Apr 11 · Nov 8
- Santa Ynez Apr 11 · Nov 8
- Lompoc Jan 20 · Dec 19
- Santa Maria Feb 4 · Dec 13
- Casmalia Feb 4 · Dec 13
- Nipomo Feb 4 · Dec 13
- Guadalupe Feb 4 · Dec 13
- New Cuyama Apr 15 · Nov 4
Frequently asked questions
When is the last frost in Los Alamos, CA?
The median last spring frost in Los Alamos, CA is January 20. There is still about a 10% chance of frost after February 24, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Los Alamos, CA?
The median first fall frost is December 19, with about a 10% chance of frost before November 27.
How long is the growing season in Los Alamos, CA?
About 333 days between the median last spring frost and first fall frost.
What planting zone is Los Alamos, CA?
Los Alamos, CA is in USDA hardiness zone 9b.