Last Frost Day

Frost history / Wilton, ND

Wilton, ND: frost dates by year

Last spring and first fall frost at NOAA station USC00329455, 1951 to 2010, measured from daily minimum temperatures.

Elevation 2,188 ft, 47.160, -100.789. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 13Sep 25
EarliestApr 25 (1978)Sep 10 (1955)
LatestJun 20 (1969)Oct 24 (1994)
Trend1.3 days earlier per decade1.1 days later per decade
Years with data3334

At 28°F (hard freeze) the median last spring date is May 6 and the median first fall date is Oct 3.

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)

Apr 15Apr 30May 15May 30Jun 14Jun 291960197019801990200020101951: May 101952: May 281953: Jun 61954: May 101955: May 101957: May 231958: May 221959: May 231960: May 71961: May 161962: May 61963: May 221967: May 131968: May 201969: Jun 201970: May 111971: May 191972: May 91975: May 21978: Apr 251981: May 101983: May 201984: May 261985: Apr 271987: May 231990: May 101991: May 71993: May 12006: May 132007: May 272008: May 112009: May 142010: May 9

First fall frost (32°F)

Aug 28Sep 12Sep 27Oct 12Oct 27Nov 111960197019801990200020101951: Sep 221952: Oct 21955: Sep 101958: Sep 251959: Sep 101960: Sep 301961: Sep 241962: Sep 201966: Oct 11967: Sep 271968: Oct 31969: Sep 231970: Sep 131971: Sep 181972: Sep 211975: Oct 11977: Oct 51978: Oct 61980: Sep 261983: Sep 191987: Oct 21988: Oct 31989: Sep 111991: Sep 181993: Sep 141994: Oct 241995: Sep 192001: Sep 232004: Oct 12005: Oct 52007: Sep 142008: Oct 102009: Oct 62010: Sep 18

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
2010May 9Sep 18May 9Oct 27
2009May 14Oct 6May 14Oct 9
2008May 11Oct 10May 3Oct 16
2007May 27Sep 14Apr 13Oct 28
2006May 13no dataMay 5no data
2005no dataOct 5no dataOct 6
2004no dataOct 1no dataOct 1
2001no dataSep 23no dataOct 5
1995no dataSep 19no dataSep 21
1994no dataOct 24no dataOct 24
1993May 1Sep 14Apr 25Oct 8
1991May 7Sep 18May 5Sep 19
1990May 10no dataMay 10no data
1989no dataSep 11no dataSep 23
1988no dataOct 3no dataOct 3
1987May 23Oct 2May 22Oct 2
1985Apr 27no dataApr 27no data
1984May 26no dataMay 26no data
1983May 20Sep 19May 16Sep 21
1981May 10no dataMay 10no data
1980no dataSep 26no dataOct 12
1978Apr 25Oct 6Apr 21Oct 7
1977no dataOct 5no dataOct 10
1975May 2Oct 1May 1Oct 25
1972May 9Sep 21May 6Sep 29
1971May 19Sep 18May 2Sep 22
1970May 11Sep 13Apr 23Sep 13
1969Jun 20Sep 23May 16Oct 8
1968May 20Oct 3May 12Oct 4
1967May 13Sep 27May 12Sep 27
1966no dataOct 1no dataOct 5
1963May 22no dataMay 22no data
1962May 6Sep 20Apr 15Oct 23
1961May 16Sep 24May 9Sep 28
1960May 7Sep 30May 3Sep 30
1959May 23Sep 10May 14Sep 16
1958May 22Sep 25May 3Sep 30
1957May 23no dataApr 16no data
1955May 10Sep 10May 8Sep 10
1954May 10no dataMay 9no data
1953Jun 6no dataMay 14no data
1952May 28Oct 2Apr 13Oct 4
1951May 10Sep 22Apr 24Sep 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.