Sac City, IA: frost dates by year

Last spring and first fall frost at NOAA station USC00137312, 1951 to 2025, measured from daily minimum temperatures.

Elevation 1,210 ft, 42.419, -94.976. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	Apr 30	Oct 6
Earliest	Apr 7 (1955)	Sep 3 (1974)
Latest	Jun 3 (1969)	Oct 29 (1973)
Trend	little change (less than half a day per decade)	little change (less than half a day per decade)
Years with data	72	74

At 28°F (hard freeze) the median last spring date is Apr 15 and the median first fall date is Oct 19.

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 9	Oct 23	Apr 9	Nov 2
2024	Apr 21	Oct 15	Apr 6	Oct 16
2023	Apr 27	Oct 10	Apr 25	Oct 28
2022	May 4	Sep 28	Apr 27	Oct 8
2021	May 11	Oct 22	Apr 22	Oct 23
2020	May 10	Oct 2	Apr 22	Oct 24
2019	Apr 29	Oct 12	Apr 29	Oct 12
2018	Apr 21	Oct 12	Apr 21	Oct 16
2017	Apr 29	Oct 27	Apr 29	Oct 28
2016	Apr 13	Oct 13	Apr 13	Oct 13
2015	Apr 23	Oct 17	Apr 4	Oct 30
2014	May 17	Oct 4	Apr 19	Oct 31
2013	May 4	Oct 13	Apr 25	Oct 25
2012	Apr 17	Sep 23	Apr 13	Oct 6
2011	May 4	Sep 15	May 3	Oct 19
2010	May 10	Oct 3	May 9	Oct 29
2009	Apr 21	Oct 7	Apr 15	Oct 10
2008	Apr 30	Oct 16	Apr 16	Oct 21
2007	Apr 16	Sep 16	Apr 14	Nov 3
2006	Apr 26	Sep 20	Apr 9	Oct 12
2005	May 6	Oct 7	May 4	Oct 25
2004	May 15	Oct 2	Apr 13	Nov 3
2003	Apr 10	Oct 1	Apr 10	Oct 2
2002	May 3	Oct 7	Apr 11	Oct 20
2001	Apr 25	Oct 6	Apr 19	Oct 17
2000	Apr 22	Oct 6	Apr 9	Oct 6
1999	Apr 19	Sep 21	Mar 27	Oct 4
1998	Apr 17	Oct 22	Mar 25	Nov 5
1997	May 13	Oct 20	May 13	Oct 22
1995	May 3	Sep 22	Apr 5	Oct 22
1994	May 1	Oct 12	Apr 8	Oct 26
1993	Apr 20	Oct 9	Apr 6	Oct 10
1992	May 7	Sep 29	Apr 18	Oct 16
1991	Apr 25	Sep 19	Apr 11	Oct 7
1990	May 3	Oct 10	Apr 18	Oct 10
1989	May 8	Sep 23	Apr 16	Oct 4
1988	Apr 20	Oct 4	Apr 20	Oct 5
1987	Apr 7	Oct 3	Apr 6	Oct 3
1986	Apr 22	Oct 6	Apr 22	Oct 14
1985	Apr 10	Oct 1	Apr 10	Oct 31
1984	Apr 30	Sep 26	Apr 5	Oct 23
1983	May 14	Sep 20	Apr 19	Nov 9
1982	no data	Oct 19	no data	Oct 20
1981	May 11	Oct 1	Apr 15	Oct 18
1980	May 8	Sep 26	Apr 14	Oct 11
1979	May 12	Oct 5	Apr 30	Oct 13
1978	May 6	Oct 8	May 3	Oct 28
1977	Apr 26	Oct 3	Apr 8	Oct 13
1976	May 8	Oct 6	May 8	Oct 6
1975	Apr 20	Sep 25	Apr 12	Oct 2
1974	Apr 24	Sep 3	Apr 24	Sep 22
1973	Apr 28	Oct 29	Apr 28	Oct 29
1972	no data	Sep 30	no data	Oct 15
1971	Apr 14	Oct 28	Apr 6	Oct 31
1970	May 2	Oct 10	Apr 4	Nov 14
1969	Jun 3	Oct 14	Apr 6	Oct 14
1968	May 5	Oct 4	Apr 5	Oct 29
1967	May 6	Sep 28	May 3	Oct 11
1966	May 10	Oct 15	May 9	Oct 16
1965	Apr 28	Sep 24	Apr 16	Oct 24
1964	Apr 9	Oct 9	Apr 8	Oct 9
1963	May 22	Oct 29	Apr 4	Oct 29
1962	Apr 19	Oct 23	Apr 15	Oct 25
1961	May 2	Sep 28	Apr 18	Sep 28
1960	Apr 30	Oct 19	Apr 30	Oct 19
1959	Apr 22	Oct 9	Apr 13	Oct 12
1958	Apr 29	Oct 1	Apr 29	Oct 26
1957	May 4	Oct 10	Apr 14	Oct 25
1956	Apr 30	Sep 30	Apr 30	Nov 8
1955	Apr 7	Oct 15	Mar 28	Oct 24
1954	May 8	Oct 18	Apr 8	Oct 31
1953	May 13	Oct 26	Apr 20	Nov 4
1952	Apr 15	Oct 5	Apr 11	Oct 6
1951	Apr 26	Sep 28	Apr 17	Oct 24

"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.