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Will it freeze in Winterset in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Fri, Nov 6: 28°F (Fri, Nov 6, 6:00 PM CST to Sat, Nov 7, 6:00 AM CST).
Tonight: forecast low 37°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST.
2 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 37°F Above 36°F · Cloudy
- Fri, Nov 6 28°F Hard freeze · Partly Cloudy
- Sat, Nov 7 36°F Frost possible · Mostly Clear
- Sun, Nov 8 39°F Above 36°F · Clear
- Mon, Nov 9 42°F Above 36°F · Clear
- Tue, Nov 10 41°F Above 36°F · Partly Cloudy
- Wed, Nov 11 42°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 Winterset
The median first fall hard-freeze date (28°F) is October 15, from NOAA’s 1991–2020 Climate Normals at Winterset 1S. 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 | Apr 27 · May 9 · May 22 | Sep 12 · Sep 26 · Oct 9 | 140 days |
| 32°F freeze | Apr 17 · Apr 30 · May 11 | Sep 20 · Oct 3 · Oct 20 | 157 days |
| 28°F hard freeze | Apr 6 · Apr 20 · May 3 | Sep 29 · Oct 15 · Oct 28 | 178 days |
Average high temperature by month
1991–2020 normals at Winterset 1S
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 Winterset, IA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Winterset 1S (station USC00139132, elevation 1,100 ft), 2.1 mi from Winterset. 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 Winterset
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Waukee, IA | 18 mi | Apr 18 | Oct 20 |
| Adel, IA | 18 mi | Apr 25 | Oct 10 |
| West Des Moines, IA | 19 mi | Apr 18 | Oct 20 |
| Norwalk, IA | 19 mi | Apr 18 | Oct 20 |
| Clive, IA | 22 mi | Apr 18 | Oct 20 |
| Indianola, IA | 23 mi | Apr 24 | Oct 12 |
| Urbandale, IA | 24 mi | Apr 19 | Oct 18 |
| Windsor Heights, IA | 24 mi | Apr 18 | Oct 20 |
| Osceola, IA | 24 mi | Apr 29 | Oct 9 |
| Grimes, IA | 25 mi | Apr 19 | Oct 18 |
Frequently asked questions
When is the last frost in Winterset?
On average, the last spring frost (32°F) in Winterset is around April 30. In about 1 year in 10 it comes after May 11, and in 9 years in 10 it comes after April 17.
When is the first frost in Winterset?
The first fall frost (32°F) usually arrives around October 3. There’s a 10% chance of a freeze by September 20 and a 90% chance by October 20.
Can it frost in Winterset 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 9.
What growing zone is Winterset?
Winterset 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 50273. See growing zones in Iowa.
More: all Iowa frost dates · Iowa growing zones · frost vs. freeze