Last Frost Day

Frost history / Elk Mtn, WY

Elk Mtn, WY: frost dates by year

Last spring and first fall frost at NOAA station USC00482995, 1951 to 2013, measured from daily minimum temperatures.

Elevation 7,265 ft, 41.688, -106.414. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianJun 8Sep 8
EarliestMay 4 (1987)Aug 7 (1969)
LatestJul 12 (1955)Oct 5 (1998)
Trend2.9 days earlier per decade2.0 days later per decade
Years with data5454

At 28°F (hard freeze) the median last spring date is May 21 and the median first fall date is Sep 19.

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 29Jul 14Jul 291960197019801990200020101951: Jun 301952: May 311953: Jun 61954: Jun 291955: Jul 121956: May 161957: Jun 231958: Jun 131961: May 261962: Jun 161963: Jul 11964: Jun 191965: Jun 51966: Jun 131968: Jul 31969: Jun 181972: May 301973: Jun 181974: Jun 91975: Jun 111976: Jun 181977: May 211978: Jun 21979: Jun 101980: May 311981: Jun 141982: Jun 101983: May 311985: Jun 111986: May 231987: May 41989: Jun 221990: Jun 21991: May 171992: Jun 161993: Jun 71994: Jun 111995: Jun 71996: Jun 31997: May 201999: May 222000: May 182001: Jun 132002: Jun 152003: Jun 92004: Jun 82005: May 312006: May 312007: Jun 82008: Jun 122009: May 172010: May 262011: Jun 42013: Jun 5

First fall frost (32°F)

Jul 29Aug 13Aug 28Sep 12Sep 27Oct 121960197019801990200020101951: Sep 91952: Sep 131955: Aug 301956: Aug 111957: Sep 11958: Aug 221959: Sep 21961: Sep 21962: Aug 241963: Aug 291964: Aug 201966: Aug 221967: Aug 311968: Aug 301969: Aug 71971: Sep 151972: Sep 141973: Sep 171974: Sep 31975: Sep 131976: Aug 271977: Sep 91978: Sep 141979: Sep 131980: Sep 221981: Sep 161983: Sep 201984: Sep 141985: Sep 131986: Sep 191987: Sep 111988: Sep 131989: Sep 21990: Sep 141991: Sep 181992: Aug 291993: Aug 311994: Sep 161995: Sep 201996: Sep 181997: Sep 241998: Oct 51999: Sep 72000: Sep 72002: Aug 112003: Sep 132004: Sep 22005: Aug 312006: Sep 22007: Sep 112009: Sep 132010: Sep 42011: Sep 42012: Sep 5

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

"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.