Iowa City, IA: frost dates by year

Last spring and first fall frost at NOAA station USC00134101, 1951 to 2025, measured from daily minimum temperatures.

Elevation 640 ft, 41.609, -91.505. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	Apr 20	Oct 12
Earliest	Mar 24 (1998)	Sep 20 (1956)
Latest	May 23 (1963)	Nov 5 (1998)
Trend	little change (less than half a day per decade)	0.9 days later per decade
Years with data	73	75

At 28°F (hard freeze) the median last spring date is Apr 12 and the median first fall date is Oct 26.

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