When is the last frost in Cooper Landing, AK?

For ZIP code 99572, the average last spring frost (32°F) is June 12, based on NOAA 1991-2020 climate normals for the Cooper Landing 5 W, AK weather station. There is a 1-in-10 chance of a frost after July 2.

When is the first frost in Cooper Landing, AK?

The average first fall frost (32°F) is September 1. There is a 1-in-10 chance of frost by August 14, so tender plants are at risk from that point on.

How long is the growing season in 99572?

In half of years, the frost-free season (between the last and first 32°F frost) is at least 78 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 99572Cooper Landing, AK

The average last spring frost in Cooper Landing is June 12 and the average first fall frost is September 1, giving a typical growing season of about 78 days. Dates are based on NOAA 1991-2020 climate normals.

Average last spring frost: Jun 12
Average first fall frost: Sep 1
Growing season: 78 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)	—	—	47 days	100%
Frost / freeze (32°F)	May 29 · Jun 12 · Jul 2	Aug 14 · Sep 1 · Sep 17	78 days	100%
Hard freeze (28°F)	May 6 · May 26 · Jun 8	Aug 31 · Sep 15 · Sep 30	114 days	100%

Where these dates come from

ZIP code 99572 is matched to the NOAA station Cooper Landing 5 W, AK, 8 km away, at 375 ft elevation (1,042 ft lower than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Cooper Landing 5 W, AK (used)	375 ft	Jun 12	Sep 1
Cooper Lake Project, AK	505 ft	May 18	Sep 27
Moose Pass 3Nw, AK	492 ft	May 31	Sep 8
Seward 19N, AK	518 ft	May 21	Sep 26

Frost dates near Cooper Landing

Moose Pass, AK 99631 · last May 31, first Sep 8
Seward, AK 99664 · last May 2, first Oct 7
Hope, AK 99605 · last May 18, first Sep 23
Sterling, AK 99672 · last May 20, first Sep 21
Girdwood, AK 99587 · last May 8, first Sep 29
Anchorage, AK 99511 · last May 5, first Sep 29
Whittier, AK 99693 · last Apr 25, first Oct 14
Indian, AK 99540 · last May 18, first Sep 23

Frequently asked questions

When is the last frost in Cooper Landing, AK?: For ZIP code 99572, the average last spring frost (32°F) is June 12, based on NOAA 1991-2020 climate normals for the Cooper Landing 5 W, AK weather station. There is a 1-in-10 chance of a frost after July 2.
When is the first frost in Cooper Landing, AK?: The average first fall frost (32°F) is September 1. There is a 1-in-10 chance of frost by August 14, so tender plants are at risk from that point on.
How long is the growing season in 99572?: In half of years, the frost-free season (between the last and first 32°F frost) is at least 78 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.