When is the last frost in Conner, MT?

Frost is possible in any month at the nearest NOAA station (Sula 3 Ene, MT), so there is no reliable average last frost date.

When is the first frost in Conner, 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 59827Conner, MT

Frost is possible in any month near Conner, based on NOAA 1991-2020 records for the Sula 3 Ene, 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)	—	—	28 days	100%
Frost / freeze (32°F)	—	—	59 days	100%
Hard freeze (28°F)	May 12 · May 28 · Jun 20	Aug 24 · Sep 9 · Sep 25	100 days	100%

Where these dates come from

ZIP code 59827 is matched to the NOAA station Sula 3 Ene, MT, 12.9 km away, at 4,475 ft elevation (272 ft lower than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Sula 3 Ene, MT (used)	4,475 ft	—	—
Darby, MT	3,880 ft	May 24	Sep 23
Sula 14 Ne, MT	5,155 ft	—	—
Hamilton, MT	3,585 ft	May 21	Sep 22

Frost dates near Conner

Darby, MT 59829 · last May 24, first Sep 23
Sula, MT 59871 · last —, first —
Grantsdale, MT 59835 · last May 21, first Sep 22
Hamilton, MT 59840 · last May 21, first Sep 22
Gibbonsville, ID 83463 · last —, first —
Corvallis, MT 59828 · last May 23, first Sep 21
Pinesdale, MT 59841 · last May 23, first Sep 21
Victor, MT 59875 · last May 23, first Sep 21

Frequently asked questions

When is the last frost in Conner, MT?: Frost is possible in any month at the nearest NOAA station (Sula 3 Ene, MT), so there is no reliable average last frost date.
When is the first frost in Conner, 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.