When is the last frost in Winnetka, CA?

For ZIP code 91306, the average last spring frost (32°F) is January 24, based on NOAA 1991-2020 climate normals for the Woodland Hills Pierce College, CA weather station. There is a 1-in-10 chance of a frost after March 5.

When is the first frost in Winnetka, CA?

The average first fall frost (32°F) is December 15. There is a 1-in-10 chance of frost by November 27, so tender plants are at risk from that point on.

How long is the growing season in 91306?

In half of years, the frost-free season (between the last and first 32°F frost) is at least 329 days long.

Are these frost dates a forecast?

No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.

Frost dates for 91306Winnetka, CA

The average last spring frost in Winnetka is January 24 and the average first fall frost is December 15, giving a typical growing season of about 329 days. Dates are based on NOAA 1991-2020 climate normals.

Average last spring frost: Jan 24
Average first fall frost: Dec 15
Growing season: 329 days

Frost risk by date

NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.

Spring dates: chance of a frost AFTER the date. Fall dates: chance of a frost BEFORE the date.
Temperature	Last spring: 90% / 50% / 10% chance	First fall: 10% / 50% / 90% chance	Growing season (50%)	Years with at least one
Light frost (36°F)	Jan 30 · Mar 2 · Apr 7	Nov 12 · Nov 29 · Dec 19	271 days	100%
Frost / freeze (32°F)	Dec 21 · Jan 24 · Mar 5	Nov 27 · Dec 15 · Jan 26	329 days	91%
Hard freeze (28°F)	Dec 5 · Dec 31 · Feb 1	Dec 1 · Dec 26 · Jan 25	365 days	35%

Where these dates come from

ZIP code 91306 is matched to the NOAA station Woodland Hills Pierce College, CA, 3 km away, at 790 ft elevation (1 ft lower than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Woodland Hills Pierce College, CA (used)	790 ft	Jan 24	Dec 15
Northridge Cal State, CA	904 ft	Jan 2	Jan 1
Van Nuys Ap, CA	770 ft	Dec 31	Dec 30
Getty Ctr, CA	1,117 ft	—	—

Frost dates near Winnetka

Winnetka, CA 91396 · last Jan 24, first Dec 15
Canoga Park, CA 91305 · last Jan 24, first Dec 15
Reseda, CA 91335 · last Dec 31, first Dec 30
Northridge, CA 91324 · last Jan 24, first Dec 15
Tarzana, CA 91357 · last Jan 24, first Dec 15
Woodland Hills, CA 91367 · last Jan 24, first Dec 15
Chatsworth, CA 91311 · last Jan 24, first Dec 15
Porter Ranch, CA 91326 · last Jan 24, first Dec 15

Frequently asked questions

When is the last frost in Winnetka, CA?: For ZIP code 91306, the average last spring frost (32°F) is January 24, based on NOAA 1991-2020 climate normals for the Woodland Hills Pierce College, CA weather station. There is a 1-in-10 chance of a frost after March 5.
When is the first frost in Winnetka, CA?: The average first fall frost (32°F) is December 15. There is a 1-in-10 chance of frost by November 27, so tender plants are at risk from that point on.
How long is the growing season in 91306?: In half of years, the frost-free season (between the last and first 32°F frost) is at least 329 days long.
Are these frost dates a forecast?: No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.