Last Frost Day

Frost history / Double Four Rch, WY

Double Four Rch, WY: frost dates by year

Last spring and first fall frost at NOAA station USC00482680, 1951 to 2005, measured from daily minimum temperatures.

Elevation 6,120 ft, 42.179, -105.402. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianJun 11Sep 5
EarliestMay 6 (1958)Aug 5 (1980)
LatestJul 26 (1995)Oct 8 (1963)
Trend3.5 days later per decade0.9 days earlier per decade
Years with data5051

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

Apr 30May 15May 30Jun 14Jun 29Jul 14Jul 29Aug 13196019701980199020001951: Jun 41952: May 121953: Jun 251954: Jun 31955: May 291956: May 171957: May 171958: May 61959: Jul 91960: Jun 231962: Jun 81963: Jun 21965: Jun 61966: Jun 131967: Jun 121969: Jun 151970: Jun 131971: May 211974: Jun 101975: Jun 171976: May 171977: May 311978: Jun 121979: Jun 101980: Jun 31981: Jun 161982: Jun 191983: May 311984: Jun 121985: Jun 191986: May 301987: Jul 131988: May 231989: Jun 221990: Jul 151991: May 141992: Jun 61993: Jul 71994: Jun 111995: Jul 261996: Jun 161997: Jul 21998: Jun 61999: May 172000: Jul 52001: Jun 162002: Jun 142003: Jun 72004: Jun 222005: Jun 11

First fall frost (32°F)

Jul 29Aug 13Aug 28Sep 12Sep 27Oct 12Oct 27196019701980199020001951: Sep 121952: Sep 21953: Sep 51954: Sep 211955: Sep 231956: Sep 11957: Sep 111958: Aug 311959: Sep 21960: Aug 251961: Sep 111962: Aug 271963: Oct 81964: Aug 201965: Aug 301966: Aug 221968: Aug 291969: Sep 231970: Sep 101974: Sep 31975: Aug 261976: Aug 271977: Sep 91978: Sep 141979: Sep 131980: Aug 51981: Sep 11982: Sep 191983: Sep 61984: Sep 151985: Sep 131986: Sep 171987: Aug 181988: Aug 231989: Sep 41990: Aug 181991: Sep 161992: Aug 271993: Aug 311994: Sep 161995: Sep 201996: Aug 71997: Sep 241998: Sep 271999: Sep 52000: Sep 72001: Sep 92002: Aug 132003: Sep 132004: Aug 122005: Aug 31

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