When is the last frost in Castaic, CA?

Frost occurs in about 37% of years at the nearest NOAA station (Newhall 5Nw, CA), so there is no reliable average last frost date.

When is the first frost in Castaic, CA?

Frost occurs in about 37% of years at the nearest NOAA station.

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 91384Castaic, CA

Frost occurs in about 37% of years near Castaic, based on NOAA 1991-2020 records for the Newhall 5Nw, CA station.

Frost occurs in about 37% of years. Frost-tender plants can usually grow year-round, but cover them if a rare cold snap is forecast.

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)	Dec 21 · Feb 22 · Apr 8	Nov 23 · Dec 19 · Feb 8	306 days	93%
Frost / freeze (32°F)	Dec 8 · Jan 8 · Mar 10	Nov 30 · Jan 1 · Feb 25	365 days	37%
Hard freeze (28°F)	—	—	365 days	3%

Where these dates come from

ZIP code 91384 is matched to the NOAA station Newhall 5Nw, CA, 10.4 km away, at 1,765 ft elevation (197 ft higher than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Newhall 5Nw, CA (used)	1,765 ft	Jan 8	Jan 1
Northridge Cal State, CA	904 ft	Jan 2	Jan 1
Sandberg, CA	4,510 ft	Apr 15	Nov 26
Fairmont, CA	3,060 ft	Apr 6	Nov 29

Frost dates near Castaic

Castaic, CA 91310 · last Jan 8, first Jan 1
Valencia, CA 91385 · last Jan 8, first Jan 1
Santa Clarita, CA 91390 · last Jan 8, first Jan 1
Stevenson Ranch, CA 91381 · last Jan 8, first Jan 1
Newhall, CA 91322 · last Jan 8, first Jan 1
Canyon Country, CA 91386 · last Jan 8, first Jan 1
Piru, CA 93040 · last Jan 8, first Jan 1
Simi Valley, CA 93063 · last Jan 8, first Jan 1

Frequently asked questions

When is the last frost in Castaic, CA?: Frost occurs in about 37% of years at the nearest NOAA station (Newhall 5Nw, CA), so there is no reliable average last frost date.
When is the first frost in Castaic, CA?: Frost occurs in about 37% of years at the nearest NOAA station.
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.