Sunnyvale, 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 Sunnyvale compares
- In a typical year, frost nights in Sunnyvale 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.
- Compared with San Jose, CA, 14 km away, the last frost here is 4 days later than there.
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
Sunnyvale, 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, 4 km away (elevation 39 ft (12 m)).
ZIP codes in Sunnyvale: 94085 94086 94087 94088 94089
Frost dates near Sunnyvale
- Mountain View Jan 6 · Dec 23
- Santa Clara Jan 12 · Dec 22
- Cupertino Jan 6 · Dec 23
- Alviso Jan 6 · Dec 23
- Los Altos Jan 6 · Dec 23
- Campbell Feb 2 · Dec 6
- Saratoga Feb 2 · Dec 6
- Milpitas Jan 12 · Dec 22
- Palo Alto Feb 1 · Dec 7
- Stanford Feb 1 · Dec 7
Frequently asked questions
When is the last frost in Sunnyvale, CA?
The median last spring frost in Sunnyvale, 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 Sunnyvale, 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 Sunnyvale, CA?
About 351 days between the median last spring frost and first fall frost.
What planting zone is Sunnyvale, CA?
Sunnyvale, CA is in USDA hardiness zone 10a.