When is the last frost in New River, AZ?

For ZIP code 85087, the average last spring frost (32°F) is January 15, based on NOAA 1991-2020 climate normals for the Castle Hot Springs, AZ weather station. There is a 1-in-10 chance of a frost after February 21.

When is the first frost in New River, AZ?

The average first fall frost (32°F) is December 22. 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 85087?

In half of years, the frost-free season (between the last and first 32°F frost) is at least 341 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 85087New River, AZ

The average last spring frost in New River is January 15 and the average first fall frost is December 22, giving a typical growing season of about 341 days. Dates are based on NOAA 1991-2020 climate normals.

Average last spring frost: Jan 15
Average first fall frost: Dec 22
Growing season: 341 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 12 · Feb 14 · Mar 10	Nov 19 · Dec 7 · Dec 25	296 days	100%
Frost / freeze (32°F)	Dec 19 · Jan 15 · Feb 21	Nov 29 · Dec 22 · Jan 26	341 days	83%
Hard freeze (28°F)	Dec 18 · Jan 9 · Feb 15	Dec 15 · Jan 6 · Feb 12	365 days	30%

Where these dates come from

ZIP code 85087 is matched to the NOAA station Castle Hot Springs, AZ, 22.6 km away, at 1,990 ft elevation (87 ft lower than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Castle Hot Springs, AZ (used)	1,990 ft	Jan 15	Dec 22
Carefree, AZ	2,530 ft	Feb 4	Dec 16
Phoenix Deer Valley Muni Ap, AZ	1,455 ft	Jan 8	Dec 25
Pinnacle Peak, AZ	2,565 ft	Jan 27	Dec 21

Frost dates near New River

Phoenix, AZ 85086 · last Jan 8, first Dec 25
Black Canyon City, AZ 85324 · last Jan 15, first Dec 22
Cave Creek, AZ 85331 · last Feb 4, first Dec 16
Carefree, AZ 85377 · last Feb 4, first Dec 16
Glendale, AZ 85310 · last Jan 8, first Dec 25
Peoria, AZ 85383 · last Jan 8, first Dec 25
Scottsdale, AZ 85266 · last Feb 4, first Dec 16
Sun City West, AZ 85375 · last Jan 20, first Dec 15

Frequently asked questions

When is the last frost in New River, AZ?: For ZIP code 85087, the average last spring frost (32°F) is January 15, based on NOAA 1991-2020 climate normals for the Castle Hot Springs, AZ weather station. There is a 1-in-10 chance of a frost after February 21.
When is the first frost in New River, AZ?: The average first fall frost (32°F) is December 22. 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 85087?: In half of years, the frost-free season (between the last and first 32°F frost) is at least 341 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.