Andover #2, SD: frost dates by year

Last spring and first fall frost at NOAA station USC00390120, 2006 to 2025, measured from daily minimum temperatures.

Elevation 1,478 ft, 45.413, -97.907. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	May 10	Oct 11
Earliest	Apr 18 (2007)	Sep 22 (2012)
Latest	May 21 (2022)	Oct 22 (2007)
Trend	1.3 days later per decade	2.2 days later per decade
Years with data	20	19

At 28°F (hard freeze) the median last spring date is Apr 30 and the median first fall date is Oct 16.

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 29	Oct 19	Apr 29	Oct 22
2024	Apr 21	Oct 14	Apr 21	Oct 14
2023	May 2	Oct 7	May 2	Oct 27
2022	May 21	Oct 7	Apr 26	Oct 7
2021	May 10	Oct 16	May 7	Oct 21
2020	May 12	Oct 15	May 12	Oct 15
2019	May 10	Oct 11	May 10	Oct 11
2018	Apr 28	Sep 28	Apr 28	Oct 4
2017	May 21	Oct 10	Apr 30	Oct 27
2016	May 15	Oct 6	May 14	Oct 7
2015	May 12	Oct 16	Apr 23	Oct 16
2014	May 16	Oct 4	May 15	Oct 4
2013	May 12	Oct 16	May 12	Oct 16
2012	Apr 22	Sep 22	Apr 11	Sep 22
2011	May 3	Oct 15	May 2	Oct 18
2010	May 8	Oct 2	Apr 8	Oct 21
2009	May 16	Sep 29	Apr 10	Oct 9
2008	May 14	Oct 14	May 11	Oct 16
2007	Apr 18	Oct 22	Apr 17	Oct 24
2006	Apr 26	no data	Apr 25	no data

"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.