Sigourney, IA: frost dates by year

Last spring and first fall frost at NOAA station USC00137678, 1951 to 2025, measured from daily minimum temperatures.

Elevation 732 ft, 41.337, -92.228. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	Apr 22	Oct 15
Earliest	Mar 28 (1999)	Sep 22 (1974)
Latest	May 13 (2021)	Nov 7 (1956)
Trend	0.5 days later per decade	little change (less than half a day per decade)
Years with data	69	70

At 28°F (hard freeze) the median last spring date is Apr 11 and the median first fall date is Oct 25.

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	Apr 17	Oct 23	Apr 9	Nov 2
2024	Apr 21	Oct 16	Apr 21	Oct 16
2023	May 3	Oct 10	Apr 24	Oct 30
2022	Apr 27	Sep 28	Apr 26	Oct 8
2021	May 13	Oct 22	Apr 22	Nov 1
2020	May 12	Oct 2	May 9	Oct 16
2019	no data	Oct 12	no data	Oct 25
2018	no data	Oct 15	no data	Oct 21
2017	Apr 8	no data	Mar 23	no data
2015	Apr 22	Oct 17	Apr 5	Oct 30
2014	Apr 19	Oct 31	Apr 19	Oct 31
2013	May 3	Oct 22	Apr 21	Oct 25
2012	Apr 13	Sep 24	Apr 11	Oct 6
2011	May 4	Oct 21	Apr 6	Oct 28
2010	May 9	Oct 29	Mar 29	Oct 29
2009	Apr 12	Oct 10	Apr 11	Oct 11
2008	Apr 29	Oct 28	Apr 3	Oct 28
2007	Apr 14	Oct 28	Apr 14	Nov 6
2006	May 6	Oct 12	Mar 27	Oct 13
2005	May 4	Oct 23	May 4	Oct 28
2004	May 4	Oct 2	Apr 14	Nov 12
2003	Apr 12	Oct 2	Apr 11	Oct 2
2002	Apr 7	Oct 13	Apr 7	Oct 17
2001	Apr 19	Oct 6	Apr 19	Oct 17
2000	Apr 13	Oct 6	Apr 13	Oct 7
1999	Mar 28	Oct 18	Mar 27	Oct 18
1998	Apr 5	Oct 22	Mar 25	Nov 5
1997	Apr 18	Oct 21	Apr 18	Oct 22
1996	Apr 28	Oct 19	Apr 11	Oct 31
1995	Apr 26	Sep 22	Apr 6	Oct 22
1994	Apr 29	Oct 25	Apr 8	Oct 26
1993	Apr 18	Oct 10	Apr 5	Oct 10
1992	Apr 22	Oct 17	Apr 13	Oct 17
1991	Apr 11	Oct 7	Mar 31	Oct 19
1990	Apr 18	no data	Apr 18	no data
1989	May 7	Oct 4	Apr 13	Nov 2
1988	Apr 29	Oct 5	Apr 27	Oct 5
1987	Apr 5	Oct 3	Apr 4	Oct 11
1986	Apr 22	Nov 4	Apr 22	Nov 9
1985	Apr 9	Nov 5	Apr 9	Nov 5
1984	Apr 6	Sep 26	Apr 1	Sep 28
1983	Apr 19	Oct 25	Apr 19	Nov 17
1982	Apr 21	Oct 21	Apr 11	Oct 22
1981	Apr 15	Oct 2	Mar 23	Oct 23
1980	Apr 15	Oct 12	Apr 14	Oct 12
1979	Apr 28	Oct 5	Apr 10	Oct 13
1978	May 1	Oct 8	Mar 27	Nov 7
1977	Apr 29	Oct 12	Apr 6	Nov 11
1976	May 3	Oct 6	Apr 12	Oct 8
1975	Apr 12	Oct 2	Apr 11	Nov 13
1974	no data	Sep 22	no data	Oct 2
1973	Apr 13	Oct 30	Apr 13	Nov 5
1972	Apr 25	Oct 18	Apr 25	Oct 18
1971	Apr 3	Oct 31	Apr 3	Nov 6
1970	May 2	Nov 3	Apr 4	Nov 3
1969	Apr 29	Oct 14	Apr 6	Oct 17
1968	Apr 25	Oct 4	Apr 6	Oct 25
1967	Apr 24	Sep 29	Apr 24	Oct 11
1966	May 10	Oct 25	Apr 21	Nov 1
1965	Apr 19	Oct 24	Apr 4	Oct 24
1964	Apr 9	Sep 28	Apr 5	Sep 28
1963	Apr 24	Oct 28	Apr 4	Nov 2
1962	Apr 16	Oct 23	Apr 16	Oct 25
1961	May 2	Oct 20	Apr 16	Nov 3
1960	Apr 10	Oct 19	Apr 10	Oct 19
1959	Apr 21	Oct 12	Apr 13	Oct 12
1958	Apr 29	Oct 1	Apr 29	Nov 21
1957	Apr 14	Oct 11	Apr 14	Oct 25
1956	Apr 30	Nov 7	Apr 24	Nov 7
1955	Apr 6	Oct 18	Apr 6	Oct 31
1954	May 7	Oct 28	Apr 4	Oct 30
1951	Apr 23	Sep 28	Apr 15	Oct 31

"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.