Mankato, MN: frost dates by year

Last spring and first fall frost at NOAA station USC00215073, 1987 to 2010, measured from daily minimum temperatures.

Elevation 850 ft, 44.154, -94.021. Download the data (JSON), NOAA daily records

Summary at 32°F

	Last spring frost	First fall frost
Median	Apr 30	Oct 2
Earliest	Apr 15 (2007)	Sep 15 (2007)
Latest	May 17 (2009)	Oct 16 (2008)
Trend	0.7 days later per decade	little change (less than half a day per decade)
Years with data	23	23

At 28°F (hard freeze) the median last spring date is Apr 18 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
2010	May 10	no data	Apr 10	no data
2009	May 17	Oct 9	Apr 12	Oct 10
2008	Apr 30	Oct 16	Apr 30	Oct 21
2007	Apr 15	Sep 15	Apr 15	Oct 28
2006	Apr 26	Sep 20	Apr 9	Oct 12
2005	May 5	Oct 8	May 4	Oct 25
2004	May 15	Oct 2	Apr 14	Oct 17
2003	Apr 22	Sep 29	Apr 10	Oct 1
2002	May 4	Oct 7	May 3	Oct 13
2001	Apr 25	Sep 25	Apr 18	Oct 17
2000	Apr 22	Sep 25	Apr 22	Oct 6
1999	Apr 18	Sep 21	Apr 14	Oct 20
1998	Apr 27	Oct 13	Apr 4	Nov 4
1997	May 13	Oct 14	May 13	Oct 22
1996	May 2	Oct 3	May 1	Oct 3
1995	May 2	Sep 22	Apr 5	Oct 22
1994	May 2	Oct 10	Apr 11	Oct 26
1993	Apr 26	Oct 2	Apr 11	Oct 3
1992	Apr 28	Sep 29	Apr 28	Oct 17
1991	Apr 25	Sep 20	Apr 24	Oct 7
1990	May 11	Oct 10	May 3	Oct 10
1989	May 7	Sep 23	May 7	Oct 3
1988	Apr 29	Oct 4	Apr 20	Oct 5
1987	no data	Oct 3	no data	Oct 3

"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.