Frost dates for 91311 — Chatsworth, CA
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 Chatsworth compares
- In a typical year, frost nights in Chatsworth fall between January 1 and January 2. In 1 year in 10 the first frost comes as early as December 9, or the last frost as late as January 27.
- Compared with Simi Valley, CA, 15 km away, the last frost here is 22 days earlier than there.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | December 10 |
| 50% (median) | January 2 |
| 10% (safe for tender plants) | January 27 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | December 9 |
| 50% (median) | January 1 |
| 90% (late) | January 25 |
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
Chatsworth, 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 Northridge Cal State, CA weather station, 6 km away (elevation 906 ft (276 m)).
ZIP codes in Chatsworth: 91311 91313
Frost dates near Chatsworth
- Porter Ranch Jan 2 · Jan 1
- Winnetka Jan 24 · Dec 15
- Northridge Jan 2 · Jan 1
- Canoga Park Jan 24 · Dec 15
- Granada Hills Jan 2 · Jan 1
- Reseda Jan 24 · Dec 15
- West Hills Jan 24 · Dec 15
- Woodland Hills Jan 24 · Dec 15
Frequently asked questions
When is the last frost in Chatsworth, CA?
The median last spring frost in Chatsworth, CA is January 2. There is still about a 10% chance of frost after January 27, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Chatsworth, CA?
The median first fall frost is January 1, with about a 10% chance of frost before December 9.
How long is the growing season in Chatsworth, CA?
About 364 days between the median last spring frost and first fall frost.
What planting zone is Chatsworth, CA?
Chatsworth, CA is in USDA hardiness zone 10a.