Harlan, IA: frost dates by year

Last spring and first fall frost at NOAA station USC00133632, 1951 to 2015, measured from daily minimum temperatures.

Elevation 1,270 ft, 41.645, -95.334. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	Apr 30	Oct 5
Earliest	Apr 6 (1977)	Sep 19 (1991)
Latest	Jun 3 (1969)	Nov 5 (1998)
Trend	0.7 days earlier per decade	0.5 days later per decade
Years with data	64	64

At 28°F (hard freeze) the median last spring date is Apr 16 and the median first fall date is Oct 17.

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