Frost history / Coggon, IA
Coggon, IA: frost dates by year
Last spring and first fall frost at NOAA station USC00131705, 2005 to 2019, measured from daily minimum temperatures.
Elevation 903 ft, 42.279, -91.525. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 4 | Oct 9 |
| Earliest | Apr 13 (2016) | Sep 15 (2007) |
| Latest | May 18 (2014) | Oct 17 (2017) |
| Trend | 4.0 days earlier per decade | 8.9 days later per decade |
| Years with data | 12 | 14 |
At 28°F (hard freeze) the median last spring date is Apr 20 and the median first fall date is Oct 21.
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 |
|---|---|---|---|---|
| 2019 | Apr 29 | Oct 12 | Apr 29 | Oct 25 |
| 2018 | Apr 30 | Oct 12 | Apr 30 | Oct 18 |
| 2017 | May 4 | Oct 17 | Apr 8 | Oct 29 |
| 2016 | Apr 13 | Oct 13 | Apr 13 | Oct 14 |
| 2015 | Apr 27 | Oct 17 | Apr 23 | Oct 17 |
| 2014 | May 18 | Oct 5 | Apr 18 | Oct 30 |
| 2013 | May 13 | Oct 14 | Apr 24 | Oct 22 |
| 2012 | no data | Sep 23 | no data | Sep 24 |
| 2011 | May 5 | no data | May 5 | no data |
| 2010 | no data | Oct 4 | no data | Oct 22 |
| 2009 | May 17 | Oct 5 | Apr 16 | Oct 10 |
| 2008 | May 5 | Oct 4 | Apr 15 | Oct 21 |
| 2007 | Apr 17 | Sep 15 | Apr 15 | Oct 26 |
| 2006 | May 6 | Oct 6 | Apr 27 | Oct 12 |
| 2005 | no data | Oct 16 | no data | Oct 26 |
"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.