Sullivan 3S, IL: frost dates by year

Last spring and first fall frost at NOAA station USC00118389, 2001 to 2023, measured from daily minimum temperatures.

Elevation 640 ft, 39.561, -88.609. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	Apr 17	Oct 18
Earliest	Apr 6 (2002)	Oct 1 (2003)
Latest	May 9 (2020)	Nov 12 (2016)
Trend	4.3 days later per decade	7.5 days later per decade
Years with data	19	17

At 28°F (hard freeze) the median last spring date is Apr 3 and the median first fall date is Nov 1.

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	Apr 24	no data	Mar 21	no data
2022	Apr 20	Oct 18	Mar 29	Nov 12
2021	Apr 21	Nov 3	Apr 3	Nov 3
2020	May 9	Oct 5	Apr 16	Oct 6
2019	Apr 16	Oct 31	Apr 1	Nov 1
2018	Apr 30	Oct 16	Apr 20	Oct 21
2017	Apr 7	Oct 29	Mar 23	Nov 9
2016	Apr 14	Nov 12	Apr 10	Nov 12
2015	Apr 24	no data	Apr 5	no data
2011	Apr 21	no data	Mar 29	no data
2010	Apr 10	Oct 22	Mar 27	Oct 29
2009	Apr 15	Oct 10	Mar 31	Nov 12
2008	Apr 15	Oct 28	Apr 3	Oct 28
2007	Apr 18	Oct 29	Apr 10	Nov 2
2006	no data	Oct 12	no data	Oct 15
2005	May 4	Oct 28	Mar 21	Nov 17
2004	Apr 13	Oct 2	Mar 22	Oct 4
2003	Apr 13	Oct 1	Apr 11	Oct 1
2002	Apr 6	Oct 13	Apr 5	Oct 13
2001	Apr 17	Oct 6	Apr 17	Nov 8

"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.