Porter Ranch, 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 Porter Ranch compares
- In a typical year, frost nights in Porter Ranch 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, 16 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
Porter Ranch, 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)).
Frost dates near Porter Ranch
- Chatsworth Jan 2 · Jan 1
- Northridge Jan 2 · Jan 1
- Winnetka Jan 24 · Dec 15
- Canoga Park Jan 24 · Dec 15
- Granada Hills Jan 2 · Jan 1
- Reseda Jan 24 · Dec 15
- West Hills Jan 24 · Dec 15
- North Hills Dec 31 · Dec 30
- Tarzana Jan 24 · Dec 15
- Woodland Hills Jan 24 · Dec 15
Frequently asked questions
When is the last frost in Porter Ranch, CA?
The median last spring frost in Porter Ranch, 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 Porter Ranch, 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 Porter Ranch, CA?
About 364 days between the median last spring frost and first fall frost.
What planting zone is Porter Ranch, CA?
Porter Ranch, CA is in USDA hardiness zone 10a.