When is the last frost in Big Sky, MT?

Frost is possible in any month at the nearest NOAA station (Big Sky 2Wnw, MT), so there is no reliable average last frost date.

When is the first frost in Big Sky, MT?

Frost is possible in any month at the nearest NOAA station.

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 59716Big Sky, MT

Frost is possible in any month near Big Sky, based on NOAA 1991-2020 records for the Big Sky 2Wnw, MT station.

Frost is possible in any month. Even summer nights can drop to freezing at this station, so protect tender plants whenever cold nights are forecast.

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)	—	—	26 days	100%
Frost / freeze (32°F)	—	—	50 days	100%
Hard freeze (28°F)	May 26 · Jun 11 · Jun 28	Aug 23 · Sep 8 · Sep 23	87 days	100%

Where these dates come from

ZIP code 59716 is matched to the NOAA station Big Sky 2Wnw, MT, 3.5 km away, at 6,590 ft elevation (631 ft lower than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Big Sky 2Wnw, MT (used)	6,590 ft	—	—
Ennis, MT	4,953 ft	Jun 16	Sep 4
Norris Madison Pwr House, MT	4,745 ft	Apr 30	Oct 10
Virginia City, MT	5,773 ft	Jun 4	Sep 18

Frost dates near Big Sky

Gallatin Gateway, MT 59730 · last —, first —
Ennis, MT 59729 · last Jun 16, first Sep 4
Cameron, MT 59720 · last Jun 4, first Sep 18
Mc Allister, MT 59740 · last Jun 16, first Sep 4
Norris, MT 59745 · last Apr 30, first Oct 10
Bozeman, MT 59718 · last May 23, first Sep 23
Emigrant, MT 59027 · last May 21, first Sep 27
Virginia City, MT 59755 · last Jun 4, first Sep 18

Frequently asked questions

When is the last frost in Big Sky, MT?: Frost is possible in any month at the nearest NOAA station (Big Sky 2Wnw, MT), so there is no reliable average last frost date.
When is the first frost in Big Sky, MT?: Frost is possible in any month at the nearest NOAA station.
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.