Donnellson, IA: frost dates by year

Last spring and first fall frost at NOAA station USC00132299, 2006 to 2025, measured from daily minimum temperatures.

Elevation 705 ft, 40.646, -91.564. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	Apr 21	Oct 25
Earliest	Mar 30 (2010)	Oct 6 (2012)
Latest	May 4 (2011)	Nov 12 (2016)
Trend	1.6 days earlier per decade	1.5 days later per decade
Years with data	19	20

At 28°F (hard freeze) the median last spring date is Apr 9 and the median first fall date is Oct 31.

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 9	Oct 24	Apr 9	Nov 2
2024	Apr 6	Oct 16	Mar 28	Nov 26
2023	Apr 24	Oct 28	Apr 7	Oct 30
2022	Apr 27	Oct 15	Apr 20	Oct 18
2021	Apr 22	Nov 2	Apr 21	Nov 2
2020	Apr 18	Oct 26	Apr 17	Oct 28
2019	Apr 28	Oct 12	Apr 1	Oct 31
2018	Apr 21	Oct 16	Apr 18	Oct 21
2017	Apr 8	Oct 29	Mar 17	Oct 29
2016	Apr 13	Nov 12	Apr 12	Nov 20
2015	Apr 24	Oct 17	Apr 4	Nov 22
2014	Apr 18	Oct 31	Apr 16	Nov 1
2013	Apr 24	Oct 23	Apr 21	Oct 25
2012	Apr 12	Oct 6	Apr 12	Oct 27
2011	May 4	Oct 28	Apr 1	Nov 5
2010	Mar 30	Oct 29	Mar 27	Oct 29
2009	Apr 22	Oct 10	Apr 9	Nov 27
2008	Apr 29	Oct 28	Apr 3	Oct 28
2007	Apr 15	Oct 25	Apr 9	Nov 7
2006	no data	Oct 12	no data	Oct 13

"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.