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Will it freeze in Hermantown in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Tonight: 25°F (Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST).
Tonight: forecast low 25°F. Hard freeze.
NWS forecast period: Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST.
7 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 25°F Hard freeze · Mostly Cloudy
- Fri, Nov 6 24°F Hard freeze · Partly Cloudy
- Sat, Nov 7 32°F Freeze · Partly Cloudy
- Sun, Nov 8 33°F Frost possible · Partly Cloudy
- Mon, Nov 9 34°F Frost possible · Mostly Clear
- Tue, Nov 10 31°F Freeze · Partly Cloudy
- Wed, Nov 11 32°F Freeze · Partly Cloudy
Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.
Frost and freeze probabilities
Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.
These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.
Average first hard freeze in Hermantown
The median first fall hard-freeze date (28°F) is October 12, from NOAA’s 1991–2020 Climate Normals at Duluth NWS. This is the 50% probability date, not a forecast for this year.
| Temperature | Last spring date 90% · 50% · 10% chance of a later freeze | First fall date 10% · 50% · 90% chance of an earlier freeze | Season |
|---|---|---|---|
| 36°F frost possible | May 16 · Jun 1 · Jun 17 | Sep 8 · Sep 22 · Oct 4 | 112 days |
| 32°F freeze | May 2 · May 18 · Jun 3 | Sep 19 · Oct 1 · Oct 14 | 135 days |
| 28°F hard freeze | Apr 22 · May 4 · May 21 | Sep 29 · Oct 12 · Oct 27 | 159 days |
Average high temperature by month
1991–2020 normals at Duluth NWS
Average low temperature by month
Months with lows near or below freezing carry frost risk
Where these frost dates come from
The frost dates for Hermantown, MN come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Duluth NWS (station USC00212250, elevation 1,433 ft), 2.8 mi from Hermantown. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.
Frost dates near Hermantown
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Duluth, MN | 5.6 mi | May 14 | Oct 12 |
| Superior, WI | 11 mi | May 6 | Oct 9 |
| Cloquet, MN | 14 mi | May 26 | Sep 23 |
| Virginia, MN | 52 mi | May 12 | Oct 1 |
| Hibbing, MN | 53 mi | Jun 5 | Sep 8 |
| Ashland, WI | 66 mi | May 20 | Oct 2 |
| Grand Rapids, MN | 68 mi | May 17 | Sep 24 |
| Rice Lake, WI | 94 mi | May 8 | Oct 2 |
| North Branch, MN | 96 mi | May 19 | Sep 25 |
| Cambridge, MN | 98 mi | May 2 | Oct 4 |
Frequently asked questions
When is the last frost in Hermantown?
On average, the last spring frost (32°F) in Hermantown is around May 18. In about 1 year in 10 it comes after June 3, and in 9 years in 10 it comes after May 2.
When is the first frost in Hermantown?
The first fall frost (32°F) usually arrives around October 1. There’s a 10% chance of a freeze by September 19 and a 90% chance by October 14.
Can it frost in Hermantown after the last frost date?
Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after June 1.
What growing zone is Hermantown?
Hermantown is in USDA Plant Hardiness Zone 4b (average annual extreme minimum temperature −25 to −20°F), based on the 2023 USDA map for ZIP code 55811. See growing zones in Minnesota.
More: all Minnesota frost dates · Minnesota growing zones · frost vs. freeze