Oelwein 1E, IA: frost dates by year

Last spring and first fall frost at NOAA station USC00136199, 2006 to 2025, measured from daily minimum temperatures.

Elevation 1,165 ft, 42.680, -91.875. Download the data (JSON) · NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	Apr 26	Oct 11
Earliest	Apr 12 (2012)	Sep 15 (2011)
Latest	May 16 (2016)	Oct 27 (2017)
Trend	little change (less than half a day per decade)	4.8 days later per decade
Years with data	20	16

At 28°F (hard freeze) the median last spring date is Apr 16 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
2025	Apr 17	no data	Apr 9	no data
2024	Apr 25	Oct 7	Apr 21	Oct 16
2023	May 4	no data	Apr 25	no data
2022	Apr 28	Oct 8	Apr 20	Oct 8
2021	Apr 26	no data	Apr 22	no data
2020	May 10	Oct 16	Apr 17	Oct 24
2019	Apr 16	Oct 12	Apr 1	Oct 12
2018	Apr 21	Oct 12	Apr 20	Oct 21
2017	Apr 29	Oct 27	Apr 28	Oct 29
2016	May 16	Oct 13	Apr 13	Nov 12
2015	Apr 24	no data	Apr 24	no data
2014	Apr 19	Oct 5	Apr 19	Oct 31
2013	May 13	Oct 19	Apr 25	Oct 20
2012	Apr 12	Sep 23	Apr 12	Oct 5
2011	May 4	Sep 15	Apr 6	Oct 21
2010	May 9	Oct 3	Apr 9	Oct 29
2009	Apr 20	Oct 10	Apr 10	Oct 10
2008	Apr 30	Oct 16	Apr 14	Oct 28
2007	Apr 16	Oct 23	Apr 15	Nov 2
2006	Apr 26	Sep 21	Apr 9	Oct 12

"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 1991–2020 frost probabilities.