When is the last frost in Atomic City, ID?

For ZIP code 83215, the average last spring frost (32°F) is June 11, based on NOAA 1991-2020 climate normals for the Idaho Falls 46 W, ID weather station. There is a 1-in-10 chance of a frost after July 1.

When is the first frost in Atomic City, ID?

The average first fall frost (32°F) is September 6. There is a 1-in-10 chance of frost by August 24, so tender plants are at risk from that point on.

How long is the growing season in 83215?

In half of years, the frost-free season (between the last and first 32°F frost) is at least 89 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 83215Atomic City, ID

The average last spring frost in Atomic City is June 11 and the average first fall frost is September 6, giving a typical growing season of about 89 days. Dates are based on NOAA 1991-2020 climate normals.

Average last spring frost: Jun 11
Average first fall frost: Sep 6
Growing season: 89 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)	—	—	63 days	100%
Frost / freeze (32°F)	May 20 · Jun 11 · Jul 1	Aug 24 · Sep 6 · Sep 21	89 days	100%
Hard freeze (28°F)	May 5 · May 23 · Jun 16	Sep 3 · Sep 18 · Oct 3	118 days	100%

Where these dates come from

ZIP code 83215 is matched to the NOAA station Idaho Falls 46 W, ID, 14.2 km away, at 4,938 ft elevation (82 ft lower than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Idaho Falls 46 W, ID (used)	4,938 ft	Jun 11	Sep 6
Howe, ID	4,820 ft	May 24	Sep 14
Arco, ID	5,325 ft	May 22	Sep 22
Blackfoot Fire Dept, ID	4,499 ft	May 5	Oct 3

Frost dates near Atomic City

Pingree, ID 83262 · last May 20, first Sep 20
Moreland, ID 83256 · last May 5, first Oct 3
Springfield, ID 83277 · last May 21, first Sep 20
Arco, ID 83213 · last May 22, first Sep 22
Blackfoot, ID 83221 · last May 5, first Oct 3
Aberdeen, ID 83210 · last May 21, first Sep 20
Basalt, ID 83218 · last May 5, first Oct 3
Firth, ID 83236 · last May 5, first Oct 3

Frequently asked questions

When is the last frost in Atomic City, ID?: For ZIP code 83215, the average last spring frost (32°F) is June 11, based on NOAA 1991-2020 climate normals for the Idaho Falls 46 W, ID weather station. There is a 1-in-10 chance of a frost after July 1.
When is the first frost in Atomic City, ID?: The average first fall frost (32°F) is September 6. There is a 1-in-10 chance of frost by August 24, so tender plants are at risk from that point on.
How long is the growing season in 83215?: In half of years, the frost-free season (between the last and first 32°F frost) is at least 89 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.