Checking current alerts… View NWS forecast and alerts.
Will it freeze in Thief River Falls 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.
6 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 25°F Hard freeze · Partly Cloudy
- Fri, Nov 6 29°F Freeze · Partly Cloudy
- Sat, Nov 7 32°F Freeze · Partly Cloudy
- Sun, Nov 8 38°F Above 36°F · Partly Cloudy
- Mon, Nov 9 32°F Freeze · 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 Thief River Falls
The median first fall hard-freeze date (28°F) is October 8, from NOAA’s 1991–2020 Climate Normals at Thief Rvr Falls 2. 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 12 · May 24 · Jun 7 | Sep 3 · Sep 18 · Sep 30 | 113 days |
| 32°F freeze | May 2 · May 14 · May 29 | Sep 14 · Sep 28 · Oct 11 | 135 days |
| 28°F hard freeze | Apr 21 · May 5 · May 20 | Sep 24 · Oct 8 · Oct 25 | 155 days |
Average high temperature by month
1991–2020 normals at Thief Rvr Falls 2
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 Thief River Falls, MN come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Thief Rvr Falls 2 (station USC00218247, elevation 1,128 ft), 1.5 mi from Thief River Falls. 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 Thief River Falls
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Crookston, MN | 30 mi | May 11 | Sep 27 |
| East Grand Forks, MN | 40 mi | May 10 | Oct 1 |
| Grand Forks, ND | 44 mi | May 10 | Oct 1 |
| Bemidji, MN | 74 mi | May 17 | Sep 26 |
| Moorhead, MN | 90 mi | May 5 | Oct 3 |
| Fargo, ND | 91 mi | May 4 | Oct 2 |
| Detroit Lakes, MN | 91 mi | May 15 | Sep 24 |
| West Fargo, ND | 93 mi | May 4 | Oct 2 |
| Horace, ND | 99 mi | May 4 | Oct 2 |
| Valley City, ND | 118 mi | May 13 | Sep 26 |
Frequently asked questions
When is the last frost in Thief River Falls?
On average, the last spring frost (32°F) in Thief River Falls is around May 14. In about 1 year in 10 it comes after May 29, and in 9 years in 10 it comes after May 2.
When is the first frost in Thief River Falls?
The first fall frost (32°F) usually arrives around September 28. There’s a 10% chance of a freeze by September 14 and a 90% chance by October 11.
Can it frost in Thief River Falls 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 May 24.
What growing zone is Thief River Falls?
Thief River Falls is in USDA Plant Hardiness Zone 4a (average annual extreme minimum temperature −30 to −25°F), based on the 2023 USDA map for ZIP code 56701. See growing zones in Minnesota.
More: all Minnesota frost dates · Minnesota growing zones · frost vs. freeze