Knightsen, CA frost dates
Frost is light and occasional here — typically a few cold nights around midwinter (about 7 a year). Cover tender plants when frost is forecast.
How Knightsen compares
- In a typical year, frost nights in Knightsen fall between December 19 and January 12. In 1 year in 10 the first frost comes as early as November 29, or the last frost as late as February 1.
- Knightsen shares its weather station with Brentwood, CA, 5 km away, so the two have the same frost dates.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | December 20 |
| 50% (median) | January 12 |
| 10% (safe for tender plants) | February 1 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | November 29 |
| 50% (median) | December 19 |
| 90% (late) | January 12 |
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
Knightsen, 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 Antioch Pumping Plt #3, CA weather station, 8 km away (elevation 59 ft (18 m)).
Frost dates near Knightsen
- Oakley Jan 12 · Dec 19
- Brentwood Jan 12 · Dec 19
- Bethel Island Jan 12 · Dec 19
- Discovery Bay Jan 19 · Dec 10
- Antioch Jan 12 · Dec 19
- Byron Jan 19 · Dec 10
- Isleton Jan 12 · Dec 19
- Holt Feb 5 · Dec 8
- Rio Vista Jan 12 · Dec 19
- Pittsburg Jan 9 · Dec 14
Frequently asked questions
When is the last frost in Knightsen, CA?
The median last spring frost in Knightsen, CA is January 12. There is still about a 10% chance of frost after February 1, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Knightsen, CA?
The median first fall frost is December 19, with about a 10% chance of frost before November 29.
How long is the growing season in Knightsen, CA?
About 341 days between the median last spring frost and first fall frost.
What planting zone is Knightsen, CA?
Knightsen, CA is in USDA hardiness zone 9b.