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Will it freeze in Watertown in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Tonight: 30°F (Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST).
Tonight: forecast low 30°F. Freeze.
NWS forecast period: Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST.
5 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 30°F Freeze · Mostly Cloudy
- Fri, Nov 6 28°F Hard freeze · Mostly Cloudy
- Sat, Nov 7 34°F Frost possible · Mostly Clear
- Sun, Nov 8 39°F Above 36°F · Mostly Clear
- Mon, Nov 9 34°F Frost possible · Mostly Clear
- Tue, Nov 10 36°F Frost possible · Partly Cloudy
- Wed, Nov 11 37°F Above 36°F · 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 Watertown
The median first fall hard-freeze date (28°F) is October 9, from NOAA’s 1991–2020 Climate Normals at Watertown Regional Airport. 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 4 · May 17 · May 31 | Sep 9 · Sep 23 · Oct 4 | 127 days |
| 32°F freeze | Apr 26 · May 7 · May 20 | Sep 19 · Sep 30 · Oct 13 | 145 days |
| 28°F hard freeze | Apr 14 · Apr 29 · May 11 | Sep 26 · Oct 9 · Oct 22 | 164 days |
Average high temperature by month
1991–2020 normals at Watertown Regional Airport
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 Watertown, SD come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Watertown Regional Airport (station USW00014946, elevation 1,748 ft), 0.4 mi from Watertown. 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 Watertown
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Brookings, SD | 45 mi | May 6 | Oct 1 |
| Madison, SD | 62 mi | May 5 | Sep 30 |
| Huron, SD | 64 mi | May 6 | Oct 2 |
| Montevideo, MN | 70 mi | May 4 | Oct 1 |
| Marshall, MN | 75 mi | May 5 | Oct 3 |
| Aberdeen, SD | 75 mi | May 8 | Sep 29 |
| Morris, MN | 76 mi | May 4 | Oct 1 |
| Mitchell, SD | 93 mi | May 2 | Oct 6 |
| Brandon, SD | 95 mi | May 1 | Oct 6 |
| Sioux Falls, SD | 97 mi | Apr 26 | Oct 13 |
Frequently asked questions
When is the last frost in Watertown?
On average, the last spring frost (32°F) in Watertown is around May 7. In about 1 year in 10 it comes after May 20, and in 9 years in 10 it comes after April 26.
When is the first frost in Watertown?
The first fall frost (32°F) usually arrives around September 30. There’s a 10% chance of a freeze by September 19 and a 90% chance by October 13.
Can it frost in Watertown 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 17.
What growing zone is Watertown?
Watertown 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 57201. See growing zones in South Dakota.
More: all South Dakota frost dates · South Dakota growing zones · frost vs. freeze