Audubon, IA: frost dates by year

Last spring and first fall frost at NOAA station USC00130385, 1951 to 2025, measured from daily minimum temperatures.

Elevation 1,280 ft, 41.707, -94.922. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	May 2	Oct 2
Earliest	Apr 2 (1955)	Sep 12 (1955)
Latest	May 23 (1963)	Oct 30 (1971)
Trend	0.7 days later per decade	little change (less than half a day per decade)
Years with data	70	71

At 28°F (hard freeze) the median last spring date is Apr 22 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	Apr 17	Oct 23	Apr 17	Oct 23
2024	Apr 22	Oct 7	Apr 19	Oct 16
2023	May 4	Oct 8	May 4	Oct 10
2022	May 22	Sep 28	Apr 27	Oct 8
2021	May 13	Sep 26	Apr 23	Oct 22
2020	May 11	Oct 2	May 9	Oct 2
2019	May 13	Oct 12	Apr 14	Oct 12
2018	Apr 27	Oct 12	Apr 26	Oct 16
2017	May 2	Oct 16	Apr 12	Oct 28
2016	Apr 13	Oct 13	Apr 13	Oct 13
2015	Apr 27	Oct 16	Apr 22	Oct 30
2014	May 17	Sep 13	Apr 18	Oct 31
2013	May 12	Oct 13	Apr 25	Oct 23
2012	Apr 23	Sep 23	Apr 12	Sep 23
2011	May 6	Sep 23	May 3	Oct 17
2010	May 9	Oct 3	May 9	Oct 19
2009	Apr 28	Oct 4	Apr 15	Oct 10
2008	May 4	Oct 16	May 4	Oct 16
2006	May 7	Sep 20	Apr 10	Oct 12
2005	May 6	Sep 29	May 6	Sep 30
2004	May 5	Oct 2	May 5	Oct 2
2003	Apr 23	Sep 26	Apr 11	Sep 29
2002	May 3	Sep 24	Apr 6	Oct 7
2000	Apr 27	Sep 21	Apr 13	Sep 22
1999	Apr 19	Sep 21	Mar 30	Oct 4
1998	Apr 19	Oct 8	Apr 6	Nov 5
1997	May 16	Oct 14	May 13	Oct 20
1996	Apr 27	Oct 3	Apr 27	Oct 24
1995	May 2	Sep 22	Apr 5	Sep 22
1994	May 1	Sep 27	Apr 9	Oct 25
1993	Apr 26	Sep 15	Apr 22	Oct 10
1992	May 6	Sep 29	May 6	Oct 17
1991	Apr 24	Sep 19	Apr 24	Sep 20
1990	May 2	Oct 10	May 2	Oct 10
1989	May 12	Sep 23	May 7	Sep 24
1988	Apr 28	Oct 4	Apr 24	Oct 5
1987	Apr 6	Oct 3	Apr 5	Oct 3
1986	Apr 22	Oct 6	Apr 22	Oct 14
1985	Apr 9	Sep 29	Apr 9	Nov 2
1984	Apr 30	Sep 26	Apr 1	Sep 29
1983	May 15	Sep 23	Apr 19	Nov 10
1982	Apr 22	Oct 16	Apr 22	Oct 20
1981	May 10	Oct 2	Apr 15	Oct 19
1980	May 8	Oct 3	May 8	Oct 12
1979	May 12	Oct 13	Apr 28	Oct 13
1978	May 2	Oct 7	Apr 21	Oct 28
1977	Apr 6	Oct 9	Apr 6	Nov 9
1976	May 7	Oct 6	May 3	Oct 8
1975	Apr 20	Oct 2	Apr 12	Oct 25
1974	Apr 16	Sep 22	Apr 8	Oct 2
1973	Apr 28	Oct 29	Apr 13	Oct 29
1972	Apr 25	Sep 30	Apr 8	Oct 18
1971	May 3	Oct 30	Apr 14	Oct 31
1970	May 2	Oct 9	Apr 4	Oct 16
1969	Apr 29	Oct 14	Apr 6	Oct 14
1968	May 5	Oct 4	Apr 25	Oct 4
1967	May 11	Sep 28	May 2	Oct 11
1966	May 10	Oct 1	May 1	Oct 16
1965	Apr 28	Sep 24	Apr 28	Oct 24
1964	Apr 9	Oct 5	Apr 9	Oct 9
1963	May 23	Oct 28	May 22	Oct 29
1962	Apr 17	Sep 20	Apr 17	Sep 20
1961	May 2	Sep 28	May 2	Sep 28
1960	May 1	Sep 30	Apr 30	Oct 16
1959	May 15	Oct 9	Apr 22	Oct 9
1958	Apr 29	Oct 1	Apr 29	Oct 11
1957	May 6	Oct 10	Apr 14	Oct 18
1956	May 4	Sep 30	Apr 30	Sep 30
1955	Apr 2	Sep 12	Mar 28	Oct 8
1954	no data	Sep 22	no data	Oct 30
1951	Apr 23	Sep 27	Apr 23	Sep 28

"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.