Roy Lake, SD: frost dates by year

Last spring and first fall frost at NOAA station USC00397326, 2000 to 2023, measured from daily minimum temperatures.

Elevation 1,810 ft, 45.709, -97.434. Download the data (JSON) · NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	May 12	Oct 9
Earliest	Apr 18 (2007)	Sep 24 (2000)
Latest	May 31 (2015)	Oct 18 (2011)
Trend	1.8 days earlier per decade	4.1 days later per decade
Years with data	18	15

At 28°F (hard freeze) the median last spring date is Apr 26 and the median first fall date is Oct 9.

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
2023	May 3	no data	May 2	no data
2022	May 1	Oct 7	Apr 28	Oct 7
2020	May 12	Oct 14	May 12	Oct 14
2019	May 7	Oct 10	Apr 16	Oct 11
2018	Apr 28	Sep 29	Apr 25	Oct 4
2017	no data	Oct 15	no data	Oct 27
2016	May 16	Oct 7	May 15	Oct 8
2015	May 31	Oct 16	Apr 24	Nov 7
2011	no data	Oct 18	no data	Oct 19
2010	May 9	no data	Apr 9	no data
2009	May 17	Oct 9	Apr 28	Oct 9
2008	May 12	Oct 16	May 11	Oct 27
2007	Apr 18	no data	Apr 15	no data
2006	Apr 26	Oct 11	Apr 25	Oct 11
2005	May 15	Oct 6	May 4	Oct 7
2004	May 15	no data	May 14	no data
2003	May 20	no data	Apr 18	no data
2002	May 24	Sep 27	May 24	Oct 9
2001	Apr 24	Oct 5	Apr 24	Oct 5
2000	May 14	Sep 24	Apr 17	Oct 6

"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.