When is the last frost in Phoenix, AZ?

For ZIP code 85019, the average last spring frost (32°F) is January 21, based on NOAA 1991-2020 climate normals for the South Phoenix, AZ weather station. There is a 1-in-10 chance of a frost after February 20.

When is the first frost in Phoenix, AZ?

The average first fall frost (32°F) is December 16. There is a 1-in-10 chance of frost by November 29, so tender plants are at risk from that point on.

How long is the growing season in 85019?

In half of years, the frost-free season (between the last and first 32°F frost) is at least 331 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 85019Phoenix, AZ

The average last spring frost in Phoenix is January 21 and the average first fall frost is December 16, giving a typical growing season of about 331 days. Dates are based on NOAA 1991-2020 climate normals.

Average last spring frost: Jan 21
Average first fall frost: Dec 16
Growing season: 331 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 16 · Feb 15 · Mar 7	Nov 16 · Dec 1 · Dec 17	289 days	100%
Frost / freeze (32°F)	Dec 24 · Jan 21 · Feb 20	Nov 29 · Dec 16 · Jan 9	331 days	94%
Hard freeze (28°F)	Dec 13 · Jan 3 · Feb 8	Dec 10 · Dec 29 · Jan 28	365 days	47%

Where these dates come from

ZIP code 85019 is matched to the NOAA station South Phoenix, AZ, 16 km away, at 1,155 ft elevation (7 ft higher than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
South Phoenix, AZ (used)	1,155 ft	Jan 21	Dec 16
Phoenix Sky Harbor Intl Ap, AZ	1,107 ft	Jan 5	Jan 3
Youngtown, AZ	1,135 ft	Jan 20	Dec 15
Laveen 3 Sse, AZ	1,135 ft	Jan 14	Dec 22

Frost dates near Phoenix

Phoenix, AZ 85017 · last Jan 21, first Dec 16
Glendale, AZ 85301 · last Jan 20, first Dec 15
Luke Air Force Base, AZ 85309 · last Jan 20, first Dec 15
Peoria, AZ 85345 · last Jan 20, first Dec 15
Tolleson, AZ 85353 · last Jan 7, first Dec 24
Sun City, AZ 85372 · last Jan 20, first Dec 15
Avondale, AZ 85392 · last Jan 7, first Dec 24
Cashion, AZ 85329 · last Jan 7, first Dec 24

Frequently asked questions

When is the last frost in Phoenix, AZ?: For ZIP code 85019, the average last spring frost (32°F) is January 21, based on NOAA 1991-2020 climate normals for the South Phoenix, AZ weather station. There is a 1-in-10 chance of a frost after February 20.
When is the first frost in Phoenix, AZ?: The average first fall frost (32°F) is December 16. There is a 1-in-10 chance of frost by November 29, so tender plants are at risk from that point on.
How long is the growing season in 85019?: In half of years, the frost-free season (between the last and first 32°F frost) is at least 331 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.