Last Frost Day

Frost history / Hennepin Wtr Trmt Plt, IL

Hennepin Wtr Trmt Plt, IL: frost dates by year

Last spring and first fall frost at NOAA station USC00114013, 1962 to 2008, measured from daily minimum temperatures.

Elevation 460 ft, 41.265, -89.338. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 3Oct 8
EarliestApr 10 (1970)Sep 11 (1993)
LatestMay 29 (1965)Nov 3 (1973)
Trend1.7 days earlier per decadelittle change (less than half a day per decade)
Years with data4145

At 28°F (hard freeze) the median last spring date is Apr 13 and the median first fall date is Oct 18.

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)

Mar 31Apr 15Apr 30May 15May 30Jun 1419701980199020001963: May 231964: Apr 151965: May 291966: May 101967: May 31968: May 161969: Apr 301970: Apr 101971: May 31972: May 101973: Apr 171974: May 71975: Apr 211976: May 71978: May 31979: Apr 101980: May 91981: May 121983: May 101984: May 161985: May 31986: May 31987: May 51988: May 191989: May 121990: Apr 191991: Apr 221992: May 281993: Apr 301994: May 21995: Apr 241997: May 161998: Apr 182000: Apr 132001: Apr 192002: May 212003: Apr 242004: May 32005: May 62006: Apr 272007: Apr 16

First fall frost (32°F)

Aug 28Sep 12Sep 27Oct 12Oct 27Nov 1119701980199020001962: Oct 241963: Oct 141964: Oct 61965: Oct 121966: Oct 21967: Oct 121968: Oct 51969: Oct 171970: Oct 161971: Sep 241972: Oct 151973: Nov 31974: Sep 231975: Oct 21976: Oct 81977: Oct 131978: Oct 81979: Oct 101980: Oct 51982: Oct 211983: Sep 221984: Sep 261985: Sep 131986: Oct 101987: Oct 31988: Oct 41989: Sep 241990: Sep 231991: Sep 201992: Sep 291993: Sep 111994: Oct 101995: Sep 231996: Oct 111997: Oct 171998: Oct 142000: Oct 72001: Oct 62002: Oct 142003: Oct 22004: Oct 52005: Oct 272006: Oct 122007: Oct 282008: Oct 28

Dots are single years. The gray line is the median, the green line the fitted trend.

Year by year

YearLast spring 32°FFirst fall 32°FLast spring 28°FFirst fall 28°F
2008no dataOct 28no dataOct 28
2007Apr 16Oct 28Apr 15Nov 2
2006Apr 27Oct 12Apr 9Oct 13
2005May 6Oct 27May 5Oct 28
2004May 3Oct 5Apr 11Oct 6
2003Apr 24Oct 2Apr 13Oct 2
2002May 21Oct 14Apr 6Oct 14
2001Apr 19Oct 6Apr 18Oct 28
2000Apr 13Oct 7Apr 12Oct 7
1998Apr 18Oct 14Apr 5Oct 22
1997May 16Oct 17Apr 18Oct 22
1996no dataOct 11no dataOct 19
1995Apr 24Sep 23Apr 5Oct 22
1994May 2Oct 10Apr 7Oct 27
1993Apr 30Sep 11Apr 20Oct 10
1992May 28Sep 29May 8Oct 17
1991Apr 22Sep 20Mar 30Oct 7
1990Apr 19Sep 23Apr 18Oct 19
1989May 12Sep 24May 7Oct 4
1988May 19Oct 4Apr 21Oct 6
1987May 5Oct 3Apr 9Oct 3
1986May 3Oct 10Apr 23Oct 15
1985May 3Sep 13Apr 12Oct 2
1984May 16Sep 26Mar 26Oct 1
1983May 10Sep 22May 10Oct 27
1982no dataOct 21no dataOct 22
1981May 12no dataApr 7no data
1980May 9Oct 5Apr 16Oct 5
1979Apr 10Oct 10Apr 10Oct 14
1978May 3Oct 8Apr 22Oct 24
1977no dataOct 13no dataOct 13
1976May 7Oct 8Apr 13Oct 18
1975Apr 21Oct 2Apr 13Nov 14
1974May 7Sep 23Apr 24Sep 23
1973Apr 17Nov 3Apr 13Nov 5
1972May 10Oct 15Apr 26Oct 15
1971May 3Sep 24Apr 23Nov 1
1970Apr 10Oct 16Apr 7Oct 16
1969Apr 30Oct 17Apr 12Oct 23
1968May 16Oct 5Apr 5Oct 30
1967May 3Oct 12Apr 24Oct 12
1966May 10Oct 2May 10Oct 20
1965May 29Oct 12Mar 31Oct 28
1964Apr 15Oct 6Apr 9Oct 6
1963May 23Oct 14Apr 14Nov 2
1962no dataOct 24no dataOct 25

"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.