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Will it freeze in Bismarck in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Tonight: 26°F (Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST).
Tonight: forecast low 26°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 26°F Hard freeze · Partly Cloudy
- Fri, Nov 6 31°F Freeze · Partly Cloudy
- Sat, Nov 7 32°F Freeze · Mostly Clear
- Sun, Nov 8 40°F Above 36°F · Partly Cloudy
- Mon, Nov 9 32°F Freeze · Partly Cloudy
- Tue, Nov 10 36°F Frost possible · Partly Cloudy
- Wed, Nov 11 36°F Frost possible · 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 Bismarck
The median first fall hard-freeze date (28°F) is October 9, from NOAA’s 1991–2020 Climate Normals at Bismarck 2.4 Nnw. 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 8 · May 20 · Jun 2 | Sep 8 · Sep 21 · Oct 4 | 123 days |
| 32°F freeze | Apr 30 · May 10 · May 23 | Sep 16 · Sep 30 · Oct 13 | 142 days |
| 28°F hard freeze | Apr 18 · May 1 · May 13 | Sep 25 · Oct 9 · Oct 22 | 161 days |
Average high temperature by month
1991–2020 normals at Bismarck 2.4 Nnw
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 Bismarck, ND come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Bismarck 2.4 Nnw (station USC00320817, elevation 1,831 ft), 1.9 mi from Bismarck. 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 Bismarck
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Mandan, ND | 5.6 mi | May 13 | Sep 27 |
| Dickinson, ND | 96 mi | May 20 | Sep 22 |
| Jamestown, ND | 98 mi | May 8 | Sep 29 |
| Minot, ND | 101 mi | May 10 | Oct 1 |
| Devils Lake, ND | 126 mi | May 6 | Oct 5 |
| Valley City, ND | 130 mi | May 13 | Sep 26 |
| Watford City, ND | 135 mi | May 9 | Sep 27 |
| Aberdeen, SD | 144 mi | May 8 | Sep 29 |
| Williston, ND | 165 mi | May 21 | Sep 21 |
| Pierre, SD | 170 mi | May 6 | Oct 3 |
Frequently asked questions
When is the last frost in Bismarck?
On average, the last spring frost (32°F) in Bismarck is around May 10. In about 1 year in 10 it comes after May 23, and in 9 years in 10 it comes after April 30.
When is the first frost in Bismarck?
The first fall frost (32°F) usually arrives around September 30. There’s a 10% chance of a freeze by September 16 and a 90% chance by October 13.
Can it frost in Bismarck 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 20.
What growing zone is Bismarck?
Bismarck 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 58505. See growing zones in North Dakota.
More: all North Dakota frost dates · North Dakota growing zones · UV index today in Bismarck · frost vs. freeze