When is the last frost in Bern, ID?

For ZIP code 83220, the average last spring frost (32°F) is June 17, based on NOAA 1991-2020 climate normals for the Bern, ID weather station. There is a 1-in-10 chance of a frost after July 4.

When is the first frost in Bern, ID?

The average first fall frost (32°F) is September 3. There is a 1-in-10 chance of frost by August 18, so tender plants are at risk from that point on.

How long is the growing season in 83220?

In half of years, the frost-free season (between the last and first 32°F frost) is at least 77 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 83220Bern, ID

The average last spring frost in Bern is June 17 and the average first fall frost is September 3, giving a typical growing season of about 77 days. Dates are based on NOAA 1991-2020 climate normals.

Average last spring frost: Jun 17
Average first fall frost: Sep 3
Growing season: 77 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)	—	—	50 days	100%
Frost / freeze (32°F)	May 31 · Jun 17 · Jul 4	Aug 18 · Sep 3 · Sep 18	77 days	100%
Hard freeze (28°F)	May 9 · May 25 · Jun 17	Sep 1 · Sep 16 · Oct 1	111 days	100%

Where these dates come from

ZIP code 83220 is matched to the NOAA station Bern, ID, 1.9 km away, at 5,964 ft elevation (14 ft lower than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Bern, ID (used)	5,964 ft	Jun 17	Sep 3
Lifton Pumping Stn, ID	5,935 ft	May 19	Sep 21
Bear Lake Sp, UT	5,928 ft	May 15	Oct 4
Soda Springs Ap, ID	5,842 ft	—	—

Frost dates near Bern

Montpelier, ID 83254 · last Jun 17, first Sep 3
Paris, ID 83261 · last Jun 17, first Sep 3
Bloomington, ID 83223 · last May 19, first Sep 21
Georgetown, ID 83239 · last Jun 17, first Sep 3
Dingle, ID 83233 · last May 19, first Sep 21
Saint Charles, ID 83272 · last May 19, first Sep 21
Thatcher, ID 83283 · last May 29, first Sep 17
Geneva, ID 83238 · last Jun 17, first Sep 3

Frequently asked questions

When is the last frost in Bern, ID?: For ZIP code 83220, the average last spring frost (32°F) is June 17, based on NOAA 1991-2020 climate normals for the Bern, ID weather station. There is a 1-in-10 chance of a frost after July 4.
When is the first frost in Bern, ID?: The average first fall frost (32°F) is September 3. There is a 1-in-10 chance of frost by August 18, so tender plants are at risk from that point on.
How long is the growing season in 83220?: In half of years, the frost-free season (between the last and first 32°F frost) is at least 77 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.