Casper Wwtp, WY: frost dates by year

Last spring and first fall frost at NOAA station USC00481569, 2001 to 2025, measured from daily minimum temperatures.

Elevation 5,097 ft, 42.861, -106.293. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	May 13	Oct 5
Earliest	Apr 30 (2009)	Sep 3 (2014)
Latest	Jun 2 (2022)	Oct 16 (2022)
Trend	1.1 days later per decade	1.3 days earlier per decade
Years with data	23	22

At 28°F (hard freeze) the median last spring date is Apr 27 and the median first fall date is Oct 13.

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	May 2	Oct 7	Apr 22	Oct 29
2024	May 22	Oct 1	May 7	Oct 31
2023	May 4	Oct 14	Apr 27	Oct 26
2022	Jun 2	Oct 16	Apr 25	Oct 17
2021	May 12	Oct 11	Apr 24	Oct 12
2020	May 8	Sep 7	Apr 17	Oct 16
2019	May 23	Oct 3	May 2	Oct 3
2018	Jun 1	Sep 26	Apr 26	Oct 11
2017	May 21	Oct 3	May 4	Oct 10
2016	May 12	Oct 7	Apr 27	Oct 12
2015	May 21	Oct 13	May 21	Oct 13
2014	May 13	Sep 3	Apr 15	Sep 3
2013	May 4	Sep 20	May 4	Oct 5
2011	May 13	Sep 21	May 3	Oct 19
2010	no data	Sep 20	no data	Nov 4
2009	Apr 30	no data	Apr 25	no data
2008	May 12	Oct 7	May 12	Oct 12
2007	May 7	Oct 15	Apr 15	Oct 16
2006	May 12	Oct 10	Apr 26	Oct 18
2005	May 13	Oct 5	May 13	Oct 5
2004	May 15	Oct 16	May 14	Nov 1
2003	May 21	Oct 5	Apr 9	Oct 14
2002	May 11	no data	May 10	no data
2001	May 21	Oct 5	May 7	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 to 2020 frost probabilities.