Last Frost Day

Frost history / Archer, WY

Archer, WY: frost dates by year

Last spring and first fall frost at NOAA station USC00480270, 1951 to 2005, measured from daily minimum temperatures.

Elevation 6,010 ft, 41.152, -104.657. Download the data (JSON) · NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 25Sep 21
EarliestApr 25 (1977)Sep 3 (1974)
LatestJun 22 (1989)Oct 27 (1963)
Trend1.5 days later per decade0.8 days earlier per decade
Years with data5454

At 28°F (hard freeze) the median last spring date is May 12 and the median first fall date is Sep 27.

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 29196019701980199020001951: Jun 41952: May 161953: May 151954: Jun 31955: May 291956: May 151957: May 231958: May 51959: May 231960: May 201961: May 171962: Jun 81963: May 221964: Jun 21965: Jun 71966: May 241967: May 201968: May 191969: Jun 131970: Jun 111971: May 191972: May 121973: Jun 31975: Jun 111976: May 171977: Apr 251978: May 151979: Jun 91980: May 141981: May 301982: Jun 91983: May 201984: Jun 101985: Jun 121986: May 251987: May 271988: May 91989: Jun 221990: May 171991: May 61992: May 281993: May 111994: Jun 91995: Jun 111996: May 291997: May 191998: Jun 61999: May 182000: May 182001: Jun 142002: May 252003: Jun 72004: Jun 12005: Jun 11

First fall frost (32°F)

Aug 28Sep 12Sep 27Oct 12Oct 27Nov 11196019701980199020001951: Sep 131952: Oct 21953: Sep 211954: Sep 211955: Sep 251956: Oct 61957: Sep 111958: Sep 251959: Sep 171960: Sep 301961: Sep 151962: Sep 91963: Oct 271964: Sep 231965: Sep 161966: Oct 11967: Sep 131968: Sep 161969: Oct 31970: Sep 121971: Sep 141972: Sep 211973: Sep 271974: Sep 31975: Sep 201976: Sep 281977: Oct 31978: Sep 201979: Sep 141980: Sep 221981: Oct 11982: Sep 171983: Sep 201984: Sep 241985: Sep 201986: Sep 271987: Sep 181988: Sep 241989: Sep 111990: Oct 31991: Sep 191992: Sep 181993: Sep 131994: Sep 221995: Sep 211996: Sep 211997: Sep 211998: Oct 51999: Sep 82000: Sep 202001: Sep 82002: Sep 212003: Sep 142004: Sep 23

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 11no dataMay 13no data
2004Jun 1Sep 23May 14Oct 14
2003Jun 7Sep 14May 11Sep 18
2002May 25Sep 21May 13Sep 22
2001Jun 14Sep 8May 21Oct 5
2000May 18Sep 20May 13Sep 23
1999May 18Sep 8May 17Sep 13
1998Jun 6Oct 5May 12Oct 12
1997May 19Sep 21May 12Oct 9
1996May 29Sep 21May 10Sep 26
1995Jun 11Sep 21May 15Sep 21
1994Jun 9Sep 22May 1Sep 22
1993May 11Sep 13May 11Sep 13
1992May 28Sep 18Apr 26Sep 18
1991May 6Sep 19May 6Sep 19
1990May 17Oct 3May 17Oct 7
1989Jun 22Sep 11May 6Oct 6
1988May 9Sep 24May 4Sep 24
1987May 27Sep 18Apr 22Sep 28
1986May 25Sep 27May 13Oct 3
1985Jun 12Sep 20Apr 27Sep 23
1984Jun 10Sep 24May 8Sep 25
1983May 20Sep 20May 18Sep 20
1982Jun 9Sep 17May 7Oct 10
1981May 30Oct 1Apr 24Oct 18
1980May 14Sep 22Apr 26Oct 10
1979Jun 9Sep 14May 11Oct 4
1978May 15Sep 20May 9Sep 21
1977Apr 25Oct 3Apr 21Oct 10
1976May 17Sep 28May 17Oct 7
1975Jun 11Sep 20May 26Sep 20
1974no dataSep 3no dataSep 28
1973Jun 3Sep 27May 13Sep 27
1972May 12Sep 21May 4Sep 21
1971May 19Sep 14May 19Sep 17
1970Jun 11Sep 12May 15Sep 26
1969Jun 13Oct 3Jun 2Oct 4
1968May 19Sep 16May 19Oct 9
1967May 20Sep 13May 14Oct 15
1966May 24Oct 1May 19Oct 1
1965Jun 7Sep 16May 10Sep 16
1964Jun 2Sep 23May 12Sep 27
1963May 22Oct 27May 20Oct 27
1962Jun 8Sep 9May 1Sep 9
1961May 17Sep 15May 6Sep 27
1960May 20Sep 30May 1Oct 15
1959May 23Sep 17May 14Sep 29
1958May 5Sep 25May 1Sep 27
1957May 23Sep 11May 17Oct 25
1956May 15Oct 6Apr 29Oct 20
1955May 29Sep 25Apr 28Oct 23
1954Jun 3Sep 21Jun 3Oct 14
1953May 15Sep 21May 14Sep 21
1952May 16Oct 2May 11Oct 5
1951Jun 4Sep 13Jun 2Sep 22

"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 1991–2020 frost probabilities.