Frost history / Postville, IA
Postville, IA: frost dates by year
Last spring and first fall frost at NOAA station USC00136766, 1988 to 2025, measured from daily minimum temperatures.
Elevation 1,165 ft, 43.090, -91.558. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Apr 29 | Oct 3 |
| Earliest | Apr 13 (2016) | Sep 13 (2014) |
| Latest | May 30 (2021) | Oct 27 (2017) |
| Trend | 1.2 days later per decade | 5.1 days later per decade |
| Years with data | 23 | 21 |
At 28°F (hard freeze) the median last spring date is Apr 23 and the median first fall date is Oct 17.
The trend is a straight-line fit through the years with a freeze. A positive spring trend means the last frost now comes later. Short or patchy records give noisy trends.
Chart
Last spring frost (32°F)
First fall frost (32°F)
Dots are single years. The gray line is the median, the green line the fitted trend.
Year by year
| Year | Last spring 32°F | First fall 32°F | Last spring 28°F | First fall 28°F |
|---|---|---|---|---|
| 2025 | Apr 26 | Oct 8 | Apr 16 | Oct 23 |
| 2024 | Apr 24 | Oct 15 | Apr 24 | Oct 16 |
| 2023 | May 3 | Oct 10 | Apr 26 | Oct 11 |
| 2022 | May 23 | Sep 28 | Apr 19 | Oct 14 |
| 2021 | May 30 | Oct 22 | May 11 | Oct 23 |
| 2020 | May 12 | Oct 2 | May 12 | Oct 19 |
| 2019 | Apr 28 | Oct 12 | Apr 28 | Oct 25 |
| 2018 | Apr 29 | Sep 29 | Apr 21 | Oct 12 |
| 2017 | May 3 | Oct 27 | Apr 28 | Oct 27 |
| 2016 | Apr 13 | Oct 13 | Apr 13 | Nov 12 |
| 2015 | Apr 27 | Oct 17 | Apr 26 | Oct 17 |
| 2014 | Apr 19 | Sep 13 | Apr 19 | Oct 31 |
| 2013 | May 13 | Oct 20 | Apr 24 | Oct 22 |
| 2012 | Apr 18 | Sep 23 | Apr 12 | Oct 7 |
| 2011 | May 4 | Sep 15 | May 4 | Oct 21 |
| 2010 | May 9 | Oct 3 | Mar 30 | Oct 3 |
| 2009 | Apr 20 | Oct 10 | Apr 15 | Oct 11 |
| 2008 | Apr 29 | no data | Apr 15 | no data |
| 2007 | Apr 15 | Sep 15 | Apr 14 | Nov 3 |
| 2003 | Apr 23 | no data | Apr 10 | no data |
| 2002 | no data | Sep 24 | no data | Sep 24 |
| 1990 | May 10 | no data | May 1 | no data |
| 1989 | May 6 | Sep 22 | May 6 | Sep 22 |
| 1988 | Apr 26 | Oct 2 | Apr 23 | Oct 4 |
"none" means the station recorded no freeze at that threshold in that half of the year. "no data" means more than 10% of the season's daily readings were missing. Years with no usable data are left out. See the methodology for the rules, and the ZIP lookup for 1991 to 2020 frost probabilities.