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Will it freeze in Charles City in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Fri, Nov 6: 25°F (Fri, Nov 6, 6:00 PM CST to Sat, Nov 7, 6:00 AM CST).
Tonight: forecast low 33°F. Frost possible.
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 33°F Frost possible · Mostly Cloudy
- Fri, Nov 6 25°F Hard freeze · Partly Cloudy
- Sat, Nov 7 33°F Frost possible · Mostly Clear
- Sun, Nov 8 35°F Frost possible · Clear
- Mon, Nov 9 38°F Above 36°F · Mostly Clear
- Tue, Nov 10 36°F Frost possible · Partly Cloudy
- Wed, Nov 11 38°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 Charles City
The median first fall hard-freeze date (28°F) is October 17, from NOAA’s 1991–2020 Climate Normals at Charles City. 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 15 · Sep 27 · Oct 9 | 141 days |
| 32°F freeze | Apr 15 · Apr 30 · May 14 | Sep 21 · Oct 6 · Oct 19 | 157 days |
| 28°F hard freeze | Apr 5 · Apr 21 · May 6 | Oct 3 · Oct 17 · Oct 29 | 178 days |
Average high temperature by month
1991–2020 normals at Charles City
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 Charles City, IA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Charles City (station USC00131402, elevation 993 ft), 0.3 mi from Charles City. 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 Charles City
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Waverly, IA | 26 mi | Apr 27 | Oct 10 |
| Mason City, IA | 27 mi | Apr 29 | Oct 7 |
| Clear Lake, IA | 35 mi | May 3 | Oct 1 |
| Cedar Falls, IA | 39 mi | Apr 27 | Oct 10 |
| Waterloo, IA | 43 mi | Apr 27 | Oct 10 |
| Austin, MN | 45 mi | Apr 30 | Oct 5 |
| Oelwein, IA | 47 mi | Apr 30 | Oct 9 |
| Decorah, IA | 48 mi | May 3 | Oct 7 |
| Iowa Falls, IA | 48 mi | Apr 28 | Oct 10 |
| Albert Lea, MN | 53 mi | Apr 27 | Oct 9 |
Frequently asked questions
When is the last frost in Charles City?
On average, the last spring frost (32°F) in Charles City is around April 30. In about 1 year in 10 it comes after May 14, and in 9 years in 10 it comes after April 15.
When is the first frost in Charles City?
The first fall frost (32°F) usually arrives around October 6. There’s a 10% chance of a freeze by September 21 and a 90% chance by October 19.
Can it frost in Charles City 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 Charles City?
Charles City 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 50616. See growing zones in Iowa.
More: all Iowa frost dates · Iowa growing zones · frost vs. freeze