Washington, IA: frost dates by year

Last spring and first fall frost at NOAA station USC00138688, 1951 to 2025, measured from daily minimum temperatures.

Elevation 687 ft, 41.282, -91.708. Download the data (JSON) · NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	Apr 21	Oct 12
Earliest	Mar 24 (1998)	Sep 15 (2007)
Latest	May 12 (2020)	Nov 8 (1956)
Trend	0.5 days later per decade	little change (less than half a day per decade)
Years with data	75	71

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 16	Oct 24
2024	Apr 22	Oct 15	Apr 5	Oct 16
2023	May 4	Oct 10	May 4	Oct 30
2022	Apr 27	Sep 28	Apr 27	Oct 8
2021	Apr 25	Oct 23	Apr 22	Nov 1
2020	May 12	Oct 16	May 9	Oct 26
2019	Apr 29	Oct 12	Apr 15	Oct 15
2018	Apr 29	no data	Apr 21	no data
2017	Apr 23	Oct 29	Apr 7	Oct 29
2016	Apr 14	Oct 13	Apr 13	Nov 12
2015	Apr 27	no data	Apr 5	no data
2014	Apr 19	Oct 11	Apr 18	Nov 1
2013	Apr 25	Oct 19	Apr 20	Oct 22
2012	Apr 21	Sep 24	Apr 13	Oct 27
2011	May 5	Oct 2	May 4	Oct 21
2010	May 9	Oct 4	Apr 9	Oct 29
2009	Apr 16	Oct 10	Apr 15	Oct 10
2008	May 4	Oct 22	Apr 3	Oct 28
2007	Apr 17	Sep 15	Apr 15	Oct 28
2006	May 6	Oct 12	Apr 9	Oct 13
2005	May 5	Oct 16	May 5	Oct 26
2004	May 4	Oct 2	Apr 14	Oct 5
2003	Apr 23	Sep 29	Apr 11	Oct 2
2002	Apr 6	Oct 13	Apr 6	Oct 13
2001	Apr 19	Oct 6	Apr 19	Oct 17
2000	Apr 13	Oct 7	Apr 13	Oct 7
1999	Apr 19	Oct 14	Mar 27	Oct 18
1998	Mar 24	Nov 5	Mar 24	Nov 5
1997	Apr 17	Oct 21	Apr 17	Oct 22
1996	Apr 16	Oct 19	Apr 9	Nov 1
1995	Apr 5	Sep 22	Apr 5	Nov 3
1994	Apr 7	Oct 25	Apr 7	Nov 16
1993	Apr 17	Oct 10	Apr 5	Oct 31
1992	Apr 22	Oct 17	Apr 12	Oct 17
1991	Apr 10	Sep 20	Mar 30	Oct 19
1990	Apr 18	Oct 19	Apr 17	Oct 22
1989	May 7	Oct 4	Apr 13	Nov 2
1988	Apr 24	Oct 5	Apr 19	Oct 26
1987	Apr 5	Oct 3	Apr 4	Oct 11
1986	Apr 22	Oct 6	Apr 22	Nov 9
1985	Apr 9	Oct 1	Apr 9	Nov 4
1984	Apr 1	Sep 29	Apr 1	Sep 29
1983	Apr 20	Sep 23	Apr 19	Sep 23
1982	Apr 21	Oct 21	Apr 11	Oct 22
1981	Apr 6	Oct 19	Apr 6	Oct 19
1980	Apr 16	Oct 12	Apr 12	Oct 28
1979	Apr 9	Oct 13	Apr 6	Oct 13
1978	May 1	Oct 8	Mar 27	Nov 7
1977	Apr 29	Oct 13	Apr 6	Nov 11
1976	Apr 12	Oct 6	Apr 12	Oct 17
1975	Apr 13	no data	Apr 6	no data
1974	Apr 9	Oct 2	Apr 8	Oct 2
1973	Apr 13	Oct 30	Apr 13	Nov 5
1972	Apr 25	Sep 30	Apr 8	Oct 15
1971	Apr 14	Nov 4	Apr 6	Nov 4
1970	May 2	Oct 10	Apr 2	Oct 16
1969	Apr 29	Oct 14	Mar 31	Oct 23
1968	Apr 25	Oct 4	Mar 24	Oct 25
1967	May 7	Sep 29	Apr 24	Oct 11
1966	May 10	Oct 17	May 10	Oct 30
1965	Apr 19	no data	Mar 31	no data
1964	Apr 9	Oct 6	Apr 9	Oct 9
1963	May 1	Oct 29	Mar 22	Nov 2
1962	Apr 16	Oct 24	Apr 16	Oct 24
1961	Apr 29	Sep 28	Apr 16	Oct 26
1960	Apr 18	Oct 20	Apr 10	Oct 20
1959	Apr 21	Oct 9	Apr 11	Oct 12
1958	Apr 29	Oct 1	Apr 29	Nov 6
1957	Apr 15	Oct 20	Apr 14	Oct 27
1956	Apr 30	Nov 8	Apr 24	Nov 9
1955	Apr 7	Oct 24	Mar 29	Oct 31
1954	May 7	Oct 18	Apr 4	Oct 30
1953	Apr 27	Oct 28	Apr 20	Oct 29
1952	Apr 15	Oct 3	Apr 11	Oct 6
1951	Apr 23	Sep 28	Apr 17	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 1991–2020 frost probabilities.