Winchester, IL: frost dates by year

Last spring and first fall frost at NOAA station USC00119331, 1998 to 2013, measured from daily minimum temperatures.

Elevation 551 ft, 39.635, -90.453. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	Apr 15	Oct 14
Earliest	Mar 30 (1999)	Oct 2 (2003)
Latest	May 5 (2011)	Oct 29 (2010)
Trend	10.6 days later per decade	4.2 days later per decade
Years with data	14	15

At 28°F (hard freeze) the median last spring date is Mar 29 and the median first fall date is Oct 28.

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
2013	Apr 21	Oct 22	Apr 20	Oct 25
2012	Apr 23	Oct 7	Mar 6	Oct 29
2011	May 5	Oct 2	Mar 31	Oct 28
2010	Apr 9	Oct 29	Mar 27	Oct 29
2009	Apr 15	no data	Mar 20	no data
2008	Apr 29	Oct 28	Apr 3	Oct 28
2007	Apr 15	Oct 28	Apr 14	Nov 2
2006	Apr 9	Oct 12	Mar 26	Oct 23
2005	May 4	Oct 26	Mar 17	Oct 28
2004	Apr 14	Oct 5	Mar 23	Oct 5
2003	Apr 12	Oct 2	Apr 11	Oct 2
2002	no data	Oct 14	no data	Nov 1
2001	Apr 19	Oct 17	Apr 19	Nov 9
2000	Apr 13	Oct 7	Mar 29	Nov 15
1999	Mar 30	Oct 5	Mar 28	Oct 18
1998	no data	Oct 22	no data	Nov 7

"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.