Frost dates for 94023 — Los Altos, CA
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 Los Altos compares
- In a typical year, frost nights in Los Altos fall between December 23 and January 6. In 1 year in 10 the first frost comes as early as December 3, or the last frost as late as February 4.
- Los Altos shares its weather station with Mountain View, CA, 3 km away, so the two have the same frost dates.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | December 16 |
| 50% (median) | January 6 |
| 10% (safe for tender plants) | February 4 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | December 3 |
| 50% (median) | December 23 |
| 90% (late) | January 16 |
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 Altos, 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 Moffett Federal Airfield, CA weather station, 6 km away (elevation 39 ft (12 m)).
ZIP codes in Los Altos: 94022 94023 94024
Frost dates near Los Altos
- Mountain View Jan 6 · Dec 23
- Stanford Feb 1 · Dec 7
- Palo Alto Feb 1 · Dec 7
- Sunnyvale Jan 6 · Dec 23
- Cupertino Jan 6 · Dec 23
- Portola Valley Mar 21 · Dec 15
- Atherton Jan 17 · Dec 12
- Alviso Jan 6 · Dec 23
Frequently asked questions
When is the last frost in Los Altos, CA?
The median last spring frost in Los Altos, CA is January 6. There is still about a 10% chance of frost after February 4, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Los Altos, CA?
The median first fall frost is December 23, with about a 10% chance of frost before December 3.
How long is the growing season in Los Altos, CA?
About 351 days between the median last spring frost and first fall frost.
What planting zone is Los Altos, CA?
Los Altos, CA is in USDA hardiness zone 9b.