Holstein, IA: frost dates by year

Last spring and first fall frost at NOAA station USC00133909, 2005 to 2019, measured from daily minimum temperatures.

Elevation 1,370 ft, 42.490, -95.549. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	Apr 28	Oct 12
Earliest	Apr 14 (2007)	Sep 22 (2012)
Latest	May 16 (2014)	Oct 28 (2010)
Trend	6.0 days later per decade	3.6 days earlier per decade
Years with data	15	15

At 28°F (hard freeze) the median last spring date is Apr 14 and the median first fall date is Oct 19.

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 28	Oct 11	Apr 14	Oct 12
2018	Apr 28	Oct 11	Apr 19	Oct 14
2017	May 2	Oct 11	Apr 11	Oct 27
2016	May 14	Oct 12	Apr 12	Oct 13
2015	Apr 22	Oct 16	Apr 22	Nov 7
2014	May 16	Oct 4	May 16	Oct 4
2013	May 12	Oct 17	Apr 25	Oct 23
2012	Apr 20	Sep 22	Apr 11	Oct 5
2011	May 3	Oct 18	May 3	Oct 19
2010	Apr 17	Oct 28	Apr 8	Oct 29
2009	Apr 28	Oct 7	Apr 14	Oct 10
2008	Apr 29	Oct 16	Apr 28	Oct 27
2007	Apr 14	Oct 28	Apr 12	Nov 1
2006	Apr 26	Oct 12	Apr 8	Oct 12
2005	May 4	Oct 7	May 3	Oct 24

"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.