Frost dates for 94403 — San Mateo, CA
Frost is light and occasional here — typically a few cold nights around midwinter (about 6 a year). Cover tender plants when frost is forecast.
How San Mateo compares
- In a typical year, frost nights in San Mateo fall between December 12 and January 17. In 1 year in 10 the first frost comes as early as November 24, or the last frost as late as February 16.
- Compared with Daly City, CA, 22 km away, the last frost here is 18 days later than there.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | December 20 |
| 50% (median) | January 17 |
| 10% (safe for tender plants) | February 16 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | November 24 |
| 50% (median) | December 12 |
| 90% (late) | January 14 |
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
San Mateo, 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 Redwood City, CA weather station, 9 km away (elevation 30 ft (9 m)).
ZIP codes in San Mateo: 94401 94402 94403 94404 94497
Frost dates near San Mateo
- Belmont Jan 17 · Dec 12
- San Carlos Jan 17 · Dec 12
- Burlingame Dec 29 · Dec 26
- Redwood City Jan 17 · Dec 12
- Millbrae Dec 29 · Dec 26
- Atherton Jan 17 · Dec 12
- Half Moon Bay Feb 6 · Dec 17
- Menlo Park Feb 25 · Nov 25
Frequently asked questions
When is the last frost in San Mateo, CA?
The median last spring frost in San Mateo, CA is January 17. There is still about a 10% chance of frost after February 16, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in San Mateo, CA?
The median first fall frost is December 12, with about a 10% chance of frost before November 24.
How long is the growing season in San Mateo, CA?
About 329 days between the median last spring frost and first fall frost.
What planting zone is San Mateo, CA?
San Mateo, CA is in USDA hardiness zone 10a.