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Will it freeze in Marshalltown in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Fri, Nov 6: 26°F (Fri, Nov 6, 6:00 PM CST to Sat, Nov 7, 6:00 AM CST).
Tonight: forecast low 35°F. Frost possible.
NWS forecast period: Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST.
4 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 35°F Frost possible · Mostly Cloudy
- Fri, Nov 6 26°F Hard freeze · Partly Cloudy
- Sat, Nov 7 34°F Frost possible · Mostly Clear
- Sun, Nov 8 36°F Frost possible · Clear
- Mon, Nov 9 39°F Above 36°F · Clear
- Tue, Nov 10 39°F Above 36°F · Partly Cloudy
- Wed, Nov 11 40°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 Marshalltown
The median first fall hard-freeze date (28°F) is October 18, from NOAA’s 1991–2020 Climate Normals at Marshalltown. 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 25 · May 7 · May 20 | Sep 16 · Sep 28 · Oct 11 | 144 days |
| 32°F freeze | Apr 13 · Apr 28 · May 11 | Sep 22 · Oct 7 · Oct 21 | 162 days |
| 28°F hard freeze | Apr 3 · Apr 17 · May 2 | Oct 1 · Oct 18 · Oct 31 | 181 days |
Average high temperature by month
1991–2020 normals at Marshalltown
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 Marshalltown, IA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Marshalltown (station USC00135198, elevation 870 ft), 2.3 mi from Marshalltown. 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 Marshalltown
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Grinnell, IA | 22 mi | May 3 | Oct 6 |
| Newton, IA | 24 mi | Apr 22 | Oct 17 |
| Nevada, IA | 29 mi | Apr 26 | Oct 12 |
| Bondurant, IA | 37 mi | Apr 23 | Oct 15 |
| Ames, IA | 37 mi | Apr 26 | Oct 8 |
| Iowa Falls, IA | 39 mi | Apr 28 | Oct 10 |
| Altoona, IA | 40 mi | Apr 23 | Oct 15 |
| Cedar Falls, IA | 40 mi | Apr 27 | Oct 10 |
| Ankeny, IA | 42 mi | Apr 23 | Oct 15 |
| Waterloo, IA | 42 mi | Apr 27 | Oct 10 |
Frequently asked questions
When is the last frost in Marshalltown?
On average, the last spring frost (32°F) in Marshalltown is around April 28. In about 1 year in 10 it comes after May 11, and in 9 years in 10 it comes after April 13.
When is the first frost in Marshalltown?
The first fall frost (32°F) usually arrives around October 7. There’s a 10% chance of a freeze by September 22 and a 90% chance by October 21.
Can it frost in Marshalltown 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 7.
What growing zone is Marshalltown?
Marshalltown 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 50158. See growing zones in Iowa.
More: all Iowa frost dates · Iowa growing zones · UV index today in Marshalltown · frost vs. freeze