When is the last frost in Brimson, MN?

Frost is possible in any month at the nearest NOAA station (Brimson 2S, MN), so there is no reliable average last frost date.

When is the first frost in Brimson, MN?

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 55602Brimson, MN

Frost is possible in any month near Brimson, based on NOAA 1991-2020 records for the Brimson 2S, MN 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)	—	—	49 days	100%
Frost / freeze (32°F)	—	—	84 days	100%
Hard freeze (28°F)	May 8 · May 27 · Jun 13	Sep 2 · Sep 20 · Oct 5	114 days	100%

Where these dates come from

ZIP code 55602 is matched to the NOAA station Brimson 2S, MN, 7.5 km away, at 1,486 ft elevation (99 ft lower than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Brimson 2S, MN (used)	1,486 ft	—	—
Two Harbors 7Nw, MN	1,355 ft	May 27	Sep 23
Isabella 14W, MN	1,740 ft	May 31	Sep 15
Two Harbors, MN	625 ft	May 12	Oct 6

Frost dates near Brimson

Hoyt Lakes, MN 55750 · last —, first —
Two Harbors, MN 55616 · last May 12, first Oct 6
Aurora, MN 55705 · last —, first —
Makinen, MN 55763 · last May 12, first Oct 1
Beaver Bay, MN 55601 · last May 15, first Oct 1
Knife River, MN 55609 · last May 12, first Oct 6
Melrude, MN 55766 · last May 27, first Sep 20
Biwabik, MN 55708 · last —, first —

Frequently asked questions

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