When is the last frost in Melrose, MT?

For ZIP code 59743, the average last spring frost (32°F) is June 10, based on NOAA 1991-2020 climate normals for the Divide, MT weather station. There is a 1-in-10 chance of a frost after July 2.

When is the first frost in Melrose, MT?

The average first fall frost (32°F) is September 7. 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 59743?

In half of years, the frost-free season (between the last and first 32°F frost) is at least 85 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 59743Melrose, MT

The average last spring frost in Melrose is June 10 and the average first fall frost is September 7, giving a typical growing season of about 85 days. Dates are based on NOAA 1991-2020 climate normals.

Average last spring frost: Jun 10
Average first fall frost: Sep 7
Growing season: 85 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)	—	—	52 days	100%
Frost / freeze (32°F)	May 23 · Jun 10 · Jul 2	Aug 24 · Sep 7 · Sep 20	85 days	100%
Hard freeze (28°F)	May 6 · May 21 · Jun 9	Sep 3 · Sep 19 · Oct 2	119 days	100%

Where these dates come from

ZIP code 59743 is matched to the NOAA station Divide, MT, 14.3 km away, at 5,350 ft elevation (163 ft higher than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Divide, MT (used)	5,350 ft	Jun 10	Sep 7
Glen 4 N, MT	5,054 ft	—	—
Twin Bridges, MT	4,625 ft	Jun 8	Sep 2
Wise Rvr 3 Wnw, MT	5,730 ft	—	—

Frost dates near Melrose

Glen, MT 59732 · last —, first —
Divide, MT 59727 · last —, first —
Wise River, MT 59762 · last —, first —
Twin Bridges, MT 59754 · last Jun 8, first Sep 2
Butte, MT 59702 · last Jun 13, first Sep 5
Silver Star, MT 59751 · last Jun 8, first Sep 2
Ramsay, MT 59748 · last Jun 13, first Sep 5
Dillon, MT 59725 · last Jun 5, first Sep 13

Frequently asked questions

When is the last frost in Melrose, MT?: For ZIP code 59743, the average last spring frost (32°F) is June 10, based on NOAA 1991-2020 climate normals for the Divide, MT weather station. There is a 1-in-10 chance of a frost after July 2.
When is the first frost in Melrose, MT?: The average first fall frost (32°F) is September 7. 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 59743?: In half of years, the frost-free season (between the last and first 32°F frost) is at least 85 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.