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Will it freeze in Spearfish in the next 7 nights?
No overnight lows at or below 32°F are forecast in Spearfish during the next 7 nights in the available NWS frost forecast.
Tonight: forecast low 35°F. Frost possible.
NWS forecast period: Thu, Nov 5, 6:00 PM MST to Fri, Nov 6, 6:00 AM MST.
1 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 35°F Frost possible · Partly Cloudy
- Fri, Nov 6 37°F Above 36°F · Mostly Clear
- Sat, Nov 7 39°F Above 36°F · Mostly Clear
- Sun, Nov 8 42°F Above 36°F · Mostly Clear
- Mon, Nov 9 39°F Above 36°F · Partly Cloudy
- Tue, Nov 10 42°F Above 36°F · Mostly Clear
- Wed, Nov 11 44°F Above 36°F · Mostly Clear
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 Spearfish
The median first fall hard-freeze date (28°F) is October 12, from NOAA’s 1991–2020 Climate Normals at Spearfish. 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 11 · May 22 · Jun 4 | Sep 9 · Sep 25 · Oct 6 | 124 days |
| 32°F freeze | Apr 29 · May 12 · May 25 | Sep 21 · Oct 2 · Oct 17 | 143 days |
| 28°F hard freeze | Apr 16 · Apr 30 · May 14 | Sep 29 · Oct 12 · Oct 25 | 164 days |
Average high temperature by month
1991–2020 normals at Spearfish
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 Spearfish, SD come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Spearfish (station USC00397882, elevation 3,633 ft), 2.7 mi from Spearfish. 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 Spearfish
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Belle Fourche, SD | 12 mi | May 10 | Sep 30 |
| Sturgis, SD | 17 mi | May 8 | Oct 3 |
| Rapid City, SD | 42 mi | May 3 | Oct 8 |
| Box Elder, SD | 45 mi | May 12 | Oct 1 |
| Gillette, WY | 85 mi | May 15 | Oct 1 |
| Douglas, WY | 144 mi | May 19 | Sep 23 |
| Sheridan, WY | 156 mi | May 21 | Sep 23 |
| Miles City, MT | 165 mi | May 8 | Sep 30 |
| Torrington, WY | 169 mi | May 11 | Sep 29 |
| Casper, WY | 169 mi | May 10 | Sep 29 |
Frequently asked questions
When is the last frost in Spearfish?
On average, the last spring frost (32°F) in Spearfish is around May 12. In about 1 year in 10 it comes after May 25, and in 9 years in 10 it comes after April 29.
When is the first frost in Spearfish?
The first fall frost (32°F) usually arrives around October 2. There’s a 10% chance of a freeze by September 21 and a 90% chance by October 17.
Can it frost in Spearfish 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 22.
What growing zone is Spearfish?
Spearfish is in USDA Plant Hardiness Zone 5b (average annual extreme minimum temperature −15 to −10°F), based on the 2023 USDA map for ZIP code 57783. See growing zones in South Dakota.
More: all South Dakota frost dates · South Dakota growing zones · frost vs. freeze