When is the last frost in Hill City, ID?

For ZIP code 83337, the average last spring frost (32°F) is June 16, based on NOAA 1991-2020 climate normals for the Hill City 1 W, ID weather station. There is a 1-in-10 chance of a frost after July 3.

When is the first frost in Hill City, ID?

The average first fall frost (32°F) is September 6. There is a 1-in-10 chance of frost by August 20, so tender plants are at risk from that point on.

How long is the growing season in 83337?

In half of years, the frost-free season (between the last and first 32°F frost) is at least 80 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 83337Hill City, ID

The average last spring frost in Hill City is June 16 and the average first fall frost is September 6, giving a typical growing season of about 80 days. Dates are based on NOAA 1991-2020 climate normals.

Average last spring frost: Jun 16
Average first fall frost: Sep 6
Growing season: 80 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)	—	—	54 days	100%
Frost / freeze (32°F)	May 31 · Jun 16 · Jul 3	Aug 20 · Sep 6 · Sep 22	80 days	100%
Hard freeze (28°F)	May 6 · May 30 · Jun 21	Sep 2 · Sep 18 · Oct 5	109 days	100%

Where these dates come from

ZIP code 83337 is matched to the NOAA station Hill City 1 W, ID, 1.8 km away, at 5,100 ft elevation (2 ft higher than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Hill City 1 W, ID (used)	5,100 ft	Jun 16	Sep 6
Fairfield Rs, ID	5,065 ft	Jun 8	Sep 14
Glenns Ferry, ID	2,466 ft	May 1	Oct 3
Hagerman 2 Sw, ID	2,897 ft	May 3	Oct 1

Frost dates near Hill City

Fairfield, ID 83327 · last Jun 8, first Sep 14
Corral, ID 83322 · last —, first —
King Hill, ID 83633 · last May 1, first Oct 3
Bliss, ID 83314 · last May 3, first Oct 1
Glenns Ferry, ID 83623 · last May 1, first Oct 3
Gooding, ID 83330 · last May 2, first Oct 14
Hammett, ID 83627 · last May 1, first Oct 3
Mountain Home, ID 83647 · last May 2, first Oct 8

Frequently asked questions

When is the last frost in Hill City, ID?: For ZIP code 83337, the average last spring frost (32°F) is June 16, based on NOAA 1991-2020 climate normals for the Hill City 1 W, ID weather station. There is a 1-in-10 chance of a frost after July 3.
When is the first frost in Hill City, ID?: The average first fall frost (32°F) is September 6. There is a 1-in-10 chance of frost by August 20, so tender plants are at risk from that point on.
How long is the growing season in 83337?: In half of years, the frost-free season (between the last and first 32°F frost) is at least 80 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.