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Will it freeze in Ames 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 36°F. Frost possible.
NWS forecast period: Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST.
3 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 36°F Frost possible · Mostly Cloudy
- Fri, Nov 6 28°F Hard freeze · Partly Cloudy
- Sat, Nov 7 35°F Frost possible · Mostly Clear
- Sun, Nov 8 37°F Above 36°F · Clear
- Mon, Nov 9 40°F Above 36°F · Mostly Clear
- Tue, Nov 10 40°F Above 36°F · Partly Cloudy
- Wed, Nov 11 41°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 Ames
The median first fall hard-freeze date (28°F) is October 19, from NOAA’s 1991–2020 Climate Normals at Ames Municipal 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 | Apr 21 · May 5 · May 17 | Sep 15 · Sep 28 · Oct 11 | 146 days |
| 32°F freeze | Apr 11 · Apr 26 · May 9 | Sep 23 · Oct 8 · Oct 21 | 164 days |
| 28°F hard freeze | Apr 1 · Apr 14 · May 1 | Oct 4 · Oct 19 · Oct 31 | 184 days |
Average high temperature by month
1991–2020 normals at Ames Municipal 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 Ames, IA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Ames Municipal Airport (station USW00094989, elevation 930 ft), 2.4 mi from Ames. 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 Ames
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Nevada, IA | 8.1 mi | Apr 26 | Oct 12 |
| Boone, IA | 13 mi | Apr 28 | Oct 12 |
| Polk City, IA | 17 mi | Apr 19 | Oct 18 |
| Ankeny, IA | 21 mi | Apr 23 | Oct 15 |
| Johnston, IA | 24 mi | Apr 19 | Oct 18 |
| Bondurant, IA | 24 mi | Apr 23 | Oct 15 |
| Grimes, IA | 26 mi | Apr 19 | Oct 18 |
| Altoona, IA | 27 mi | Apr 23 | Oct 15 |
| Perry, IA | 27 mi | Apr 25 | Oct 10 |
| Urbandale, IA | 28 mi | Apr 19 | Oct 18 |
Frequently asked questions
When is the last frost in Ames?
On average, the last spring frost (32°F) in Ames is around April 26. In about 1 year in 10 it comes after May 9, and in 9 years in 10 it comes after April 11.
When is the first frost in Ames?
The first fall frost (32°F) usually arrives around October 8. There’s a 10% chance of a freeze by September 23 and a 90% chance by October 21.
Can it frost in Ames 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 5.
What growing zone is Ames?
Ames 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 50012. See growing zones in Iowa.
More: all Iowa frost dates · Iowa growing zones · UV index today in Ames · frost vs. freeze