Oglala 1S, SD: frost dates by year

Last spring and first fall frost at NOAA station USC00396227, 1999 to 2016, measured from daily minimum temperatures.

Elevation 2,995 ft, 43.175, -102.746. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	May 13	Oct 3
Earliest	Apr 23 (2001)	Sep 14 (2007)
Latest	May 24 (2002)	Oct 16 (2015)
Trend	1.1 days later per decade	7.5 days later per decade
Years with data	15	15

At 28°F (hard freeze) the median last spring date is May 5 and the median first fall date is Oct 17.

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
2016	May 14	no data	Apr 11	no data
2015	May 21	Oct 16	Apr 22	Oct 16
2014	May 15	Oct 3	May 15	Oct 29
2013	May 5	Oct 5	May 5	Oct 18
2012	May 13	no data	Mar 22	no data
2011	May 5	Oct 15	Apr 20	Oct 19
2010	May 13	Oct 13	May 8	Nov 4
2009	no data	Sep 26	no data	Oct 3
2008	May 11	Oct 3	May 11	Oct 3
2007	no data	Sep 14	no data	Oct 22
2006	no data	Sep 19	no data	Oct 10
2005	May 12	Sep 20	May 5	Oct 3
2004	May 14	Oct 14	May 14	Nov 2
2003	May 20	Oct 1	May 20	Oct 26
2002	May 24	Oct 14	May 24	Oct 14
2001	Apr 23	no data	Apr 23	no data
2000	May 13	Sep 23	Apr 17	Oct 6
1999	May 12	Sep 27	Apr 18	Oct 17

"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.