Last Frost Day

Frost history / Clark 3NE, WY

Clark 3NE, WY: frost dates by year

Last spring and first fall frost at NOAA station USC00481775, 1961 to 2025, measured from daily minimum temperatures.

Elevation 4,117 ft, 44.936, -109.137. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 23Sep 17
EarliestMay 5 (2011)Aug 23 (2015)
LatestJun 19 (2024)Oct 15 (1963)
Trend0.6 days earlier per decade1.7 days later per decade
Years with data5758

At 28°F (hard freeze) the median last spring date is May 9 and the median first fall date is Sep 28.

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 291970198019902000201020201962: May 61963: May 221964: May 121965: May 271966: May 231967: Jun 31968: May 201970: May 151971: May 181972: May 131973: Jun 181974: Jun 11975: May 291976: Jun 151977: May 291979: Jun 91981: Jun 141983: Jun 11984: May 251985: May 301986: May 221987: Jun 21990: May 161991: May 61992: May 131994: May 71995: May 291996: May 101997: May 121998: Jun 51999: May 172000: Jun 12001: Jun 52002: May 242003: May 202004: Jun 122005: May 122006: May 112007: May 242008: Jun 112009: May 162010: May 232011: May 52012: May 262013: May 62014: May 142015: May 112016: May 122017: May 272018: Jun 122019: Jun 92020: May 82021: May 302022: May 252023: May 102024: Jun 192025: May 7

First fall frost (32°F)

Aug 13Aug 28Sep 12Sep 27Oct 12Oct 271970198019902000201020201961: Sep 31962: Sep 41963: Oct 151964: Sep 71965: Sep 51966: Sep 301967: Oct 51968: Sep 161969: Sep 151970: Sep 101971: Sep 171972: Sep 141973: Sep 151974: Sep 21975: Sep 121976: Aug 261977: Sep 91980: Sep 161983: Sep 101985: Sep 271986: Sep 221987: Sep 171990: Sep 291991: Sep 181992: Aug 251993: Sep 141994: Sep 221995: Sep 211996: Sep 231997: Sep 201998: Oct 61999: Sep 82000: Sep 202001: Oct 52002: Sep 222003: Sep 142004: Sep 212005: Oct 52006: Sep 242007: Sep 102008: Sep 82009: Sep 222010: Sep 72011: Sep 212012: Sep 122013: Oct 42014: Sep 122015: Aug 232016: Oct 52017: Sep 172018: Sep 252019: Sep 302020: Sep 92021: Sep 212022: Oct 82023: Oct 72024: Sep 222025: Oct 7

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
2025May 7Oct 7Apr 23Oct 7
2024Jun 19Sep 22May 4Oct 1
2023May 10Oct 7Apr 28Oct 25
2022May 25Oct 8May 22Oct 14
2021May 30Sep 21May 12Sep 21
2020May 8Sep 9May 8Sep 9
2019Jun 9Sep 30May 10Oct 3
2018Jun 12Sep 25Apr 27Sep 26
2017May 27Sep 17May 14Oct 3
2016May 12Oct 5May 12Oct 11
2015May 11Aug 23May 11Oct 16
2014May 14Sep 12May 13Sep 12
2013May 6Oct 4May 2Oct 5
2012May 26Sep 12May 8Oct 6
2011May 5Sep 21May 5Sep 21
2010May 23Sep 7May 8Oct 12
2009May 16Sep 22May 2Sep 28
2008Jun 11Sep 8May 3Oct 9
2007May 24Sep 10May 7Sep 10
2006May 11Sep 24May 6Oct 13
2005May 12Oct 5May 3Oct 6
2004Jun 12Sep 21May 15Oct 2
2003May 20Sep 14May 20Sep 14
2002May 24Sep 22May 9Sep 22
2001Jun 5Oct 5May 21Oct 5
2000Jun 1Sep 20May 13Sep 22
1999May 17Sep 8May 11Sep 28
1998Jun 5Oct 6Apr 28Oct 6
1997May 12Sep 20May 9Oct 12
1996May 10Sep 23May 6Sep 23
1995May 29Sep 21May 23Sep 22
1994May 7Sep 22Apr 30Sep 22
1993no dataSep 14no dataSep 14
1992May 13Aug 25May 2Aug 26
1991May 6Sep 18May 6Oct 4
1990May 16Sep 29May 16Oct 3
1987Jun 2Sep 17May 20Sep 17
1986May 22Sep 22May 22Oct 12
1985May 30Sep 27May 15Sep 28
1984May 25no dataMay 8no data
1983Jun 1Sep 10May 31Sep 19
1981Jun 14no dataMay 11no data
1980no dataSep 16no dataOct 11
1979Jun 9no dataJun 8no data
1977May 29Sep 9May 5Oct 2
1976Jun 15Aug 26May 3Sep 9
1975May 29Sep 12May 26Sep 19
1974Jun 1Sep 2May 17Sep 2
1973Jun 18Sep 15Jun 18Sep 17
1972May 13Sep 14May 2Sep 24
1971May 18Sep 17May 8Sep 18
1970May 15Sep 10May 15Sep 12
1969no dataSep 15no dataOct 5
1968May 20Sep 16May 20Sep 17
1967Jun 3Oct 5May 13Oct 17
1966May 23Sep 30May 23Sep 30
1965May 27Sep 5May 18Sep 16
1964May 12Sep 7Apr 23Sep 27
1963May 22Oct 15Apr 25Oct 21
1962May 6Sep 4Apr 30Sep 9
1961no dataSep 3no dataSep 14

"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.