San Ysidro (San Diego), CA frost dates
Frost is light and occasional here — typically a few cold nights around midwinter (about 1 a year). Cover tender plants when frost is forecast.
How San Ysidro compares
- In a typical year, frost nights in San Ysidro fall between December 31 and January 6. In 1 year in 10 the first frost comes as early as December 11, or the last frost as late as February 5.
- Nearby Chula Vista, CA, 8 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 13 |
| 50% (median) | January 6 |
| 10% (safe for tender plants) | February 5 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | December 11 |
| 50% (median) | December 31 |
| 90% (late) | January 30 |
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 Ysidro, 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 San Diego Brown Fld, CA weather station, 6 km away (elevation 515 ft (157 m)).
Frost dates near San Ysidro
- Imperial Beach rare frost
- Chula Vista rare frost
- Bonita rare frost
- National City rare frost
- Coronado rare frost
- Lemon Grove Jan 6 · Dec 21
- Spring Valley Jan 6 · Dec 21
- La Mesa Jan 6 · Dec 21
- San Diego rare frost
- Jamul Jan 6 · Dec 21
Frequently asked questions
When is the last frost in San Ysidro, CA?
The median last spring frost in San Ysidro, CA is January 6. There is still about a 10% chance of frost after February 5, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in San Ysidro, CA?
The median first fall frost is December 31, with about a 10% chance of frost before December 11.
How long is the growing season in San Ysidro, CA?
About 359 days between the median last spring frost and first fall frost.
What planting zone is San Ysidro, CA?
San Ysidro, CA is in USDA hardiness zone 10b.