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Will it freeze in Superior 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 23°F Hard freeze · Partly Cloudy
- Sat, Nov 7 30°F Freeze · Partly Cloudy
- Sun, Nov 8 31°F Freeze · Partly Cloudy
- Mon, Nov 9 33°F Frost possible · Mostly Clear
- Tue, Nov 10 28°F Hard freeze · Partly Cloudy
- Wed, Nov 11 29°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 Superior
The median first fall hard-freeze date (28°F) is October 24, from NOAA’s 1991–2020 Climate Normals at Superior. 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 6 · May 21 · Jun 8 | Sep 15 · Sep 28 · Oct 11 | 130 days |
| 32°F freeze | Apr 24 · May 6 · May 25 | Sep 24 · Oct 9 · Oct 24 | 154 days |
| 28°F hard freeze | Apr 10 · Apr 24 · May 9 | Oct 6 · Oct 24 · Nov 7 | 181 days |
Average high temperature by month
1991–2020 normals at Superior
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 Superior, WI come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Superior (station USC00478349, elevation 607 ft), 2.4 mi from Superior. 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 Superior
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Duluth, MN | 6.2 mi | May 14 | Oct 12 |
| Hermantown, MN | 11 mi | May 18 | Oct 1 |
| Cloquet, MN | 20 mi | May 26 | Sep 23 |
| Ashland, WI | 58 mi | May 20 | Oct 2 |
| Virginia, MN | 62 mi | May 12 | Oct 1 |
| Hibbing, MN | 63 mi | Jun 5 | Sep 8 |
| Grand Rapids, MN | 78 mi | May 17 | Sep 24 |
| Rice Lake, WI | 85 mi | May 8 | Oct 2 |
| North Branch, MN | 92 mi | May 19 | Sep 25 |
| Cambridge, MN | 96 mi | May 2 | Oct 4 |
Frequently asked questions
When is the last frost in Superior?
On average, the last spring frost (32°F) in Superior is around May 6. In about 1 year in 10 it comes after May 25, and in 9 years in 10 it comes after April 24.
When is the first frost in Superior?
The first fall frost (32°F) usually arrives around October 9. There’s a 10% chance of a freeze by September 24 and a 90% chance by October 24.
Can it frost in Superior 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 21.
What growing zone is Superior?
Superior is in USDA Plant Hardiness Zone 5a (average annual extreme minimum temperature −20 to −15°F), based on the 2023 USDA map for ZIP code 55802. See growing zones in Wisconsin.
More: all Wisconsin frost dates · Wisconsin growing zones · UV index today in Superior · frost vs. freeze