Last Frost Day

Frost history / Saratoga, WY

Saratoga, WY: frost dates by year

Last spring and first fall frost at NOAA station USC00487990, 1951 to 2007, measured from daily minimum temperatures.

Elevation 6,790 ft, 41.453, -106.805. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianJun 2Sep 13
EarliestMay 4 (1992)Aug 16 (1968)
LatestJun 29 (1954)Sep 27 (1998)
Trend2.2 days earlier per decade1.8 days later per decade
Years with data5050

At 28°F (hard freeze) the median last spring date is May 16 and the median first fall date is Sep 22.

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 14196019701980199020001952: May 311954: Jun 291957: Jun 231958: May 161959: Jun 11960: Jun 211961: May 171962: Jun 81963: May 271964: Jun 21965: May 281966: Jun 131969: Jun 131970: Jun 131971: May 241972: May 301973: Jun 181974: Jun 81975: Jun 111976: Jun 141977: May 291978: Jun 121979: Jun 91980: May 261981: Jun 151982: Jun 191983: Jun 141984: Jun 101985: May 311986: May 271987: Jun 31988: May 221989: Jun 221990: May 261991: May 131992: May 41993: Jun 41994: May 211995: May 231996: May 211997: May 191998: Jun 171999: May 172000: Jun 22002: Jun 112003: May 202004: Jun 22005: May 272006: May 312007: Jun 9

First fall frost (32°F)

Jul 29Aug 13Aug 28Sep 12Sep 27Oct 12196019701980199020001951: Sep 101952: Sep 21954: Sep 161956: Aug 311957: Sep 111958: Sep 161959: Sep 21960: Sep 261961: Sep 21962: Aug 241963: Sep 251964: Aug 221965: Aug 311966: Aug 231968: Aug 161969: Sep 251970: Sep 101971: Sep 151972: Sep 141973: Sep 171974: Aug 211975: Aug 251976: Aug 271977: Sep 91978: Sep 141979: Sep 131980: Sep 221981: Sep 181982: Sep 241983: Sep 201984: Sep 221985: Sep 131986: Sep 171987: Sep 181988: Sep 121989: Sep 41990: Sep 231991: Sep 151992: Sep 81993: Aug 311994: Sep 51995: Sep 211996: Sep 191997: Sep 241998: Sep 271999: Sep 82003: Sep 132004: Sep 232005: Aug 312006: Sep 4

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
2007Jun 9no dataMay 7no data
2006May 31Sep 4May 11Oct 13
2005May 27Aug 31May 2Sep 26
2004Jun 2Sep 23Jun 1Oct 11
2003May 20Sep 13May 20Sep 13
2002Jun 11no dataMay 9no data
2000Jun 2no dataMay 14no data
1999May 17Sep 8May 17Sep 13
1998Jun 17Sep 27May 12Oct 6
1997May 19Sep 24May 12Oct 13
1996May 21Sep 19May 5Sep 23
1995May 23Sep 21May 14Sep 21
1994May 21Sep 5May 1Sep 22
1993Jun 4Aug 31May 11Sep 14
1992May 4Sep 8Apr 26Sep 28
1991May 13Sep 15May 5Sep 16
1990May 26Sep 23May 17Oct 8
1989Jun 22Sep 4Jun 22Oct 3
1988May 22Sep 12May 3Sep 29
1987Jun 3Sep 18Apr 22Sep 18
1986May 27Sep 17May 23Sep 29
1985May 31Sep 13May 31Sep 13
1984Jun 10Sep 22May 28Sep 25
1983Jun 14Sep 20May 31Sep 20
1982Jun 19Sep 24Jun 9Oct 8
1981Jun 15Sep 18May 12Oct 1
1980May 26Sep 22May 14Sep 22
1979Jun 9Sep 13Jun 1Sep 14
1978Jun 12Sep 14May 9Sep 19
1977May 29Sep 9May 22Sep 18
1976Jun 14Aug 27Jun 14Sep 28
1975Jun 11Aug 25Jun 11Sep 19
1974Jun 8Aug 21May 22Sep 3
1973Jun 18Sep 17May 28Sep 17
1972May 30Sep 14May 3Sep 26
1971May 24Sep 15May 24Sep 15
1970Jun 13Sep 10Jun 1Sep 10
1969Jun 13Sep 25May 10Oct 3
1968no dataAug 16no dataSep 23
1966Jun 13Aug 23Jun 13Oct 1
1965May 28Aug 31May 27Sep 16
1964Jun 2Aug 22May 31Sep 3
1963May 27Sep 25May 21Oct 16
1962Jun 8Aug 24May 16Sep 9
1961May 17Sep 2May 6Sep 14
1960Jun 21Sep 26May 25Sep 30
1959Jun 1Sep 2May 21Sep 22
1958May 16Sep 16May 5Sep 25
1957Jun 23Sep 11Apr 28Sep 11
1956no dataAug 31no dataAug 31
1954Jun 29Sep 16Jun 8Sep 19
1952May 31Sep 2May 10Sep 14
1951no dataSep 10no dataSep 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 to 2020 frost probabilities.