Last Frost Day

Frost history / Torrington Exp Farm, WY

Torrington Exp Farm, WY: frost dates by year

Last spring and first fall frost at NOAA station USC00488995, 1951 to 2004, measured from daily minimum temperatures.

Elevation 4,098 ft, 42.080, -104.224. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 15Sep 19
EarliestApr 21 (1987)Aug 28 (1964)
LatestJun 14 (1969)Oct 15 (1963)
Trendlittle change (less than half a day per decade)1.4 days later per decade
Years with data5251

At 28°F (hard freeze) the median last spring date is May 2 and the median first fall date is Sep 29.

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 31952: May 111953: May 141954: May 291955: May 101956: May 141957: May 171958: May 21959: May 141960: May 201961: May 151962: May 21963: May 201964: Jun 21965: May 111966: May 241967: May 151968: May 201969: Jun 141970: May 151971: May 71972: May 31974: May 221975: May 261976: May 181977: Apr 231978: Jun 21979: May 121980: May 141981: May 141982: May 191984: May 71985: Jun 111986: May 221987: Apr 211988: May 81989: May 71990: May 171991: May 61992: May 271993: May 111994: May 21995: May 231996: May 101997: May 191998: Jun 61999: May 122000: May 132001: May 252002: May 252003: May 212004: May 14

First fall frost (32°F)

Aug 13Aug 28Sep 12Sep 27Oct 12Oct 27196019701980199020001951: Sep 131952: Sep 21953: Sep 211954: Sep 191955: Sep 251956: Sep 11957: Sep 111958: Sep 161959: Sep 291961: Sep 131962: Sep 91963: Oct 151964: Aug 281965: Sep 161966: Oct 11967: Sep 271969: Oct 51970: Sep 101972: Sep 211973: Sep 151974: Sep 31975: Sep 201976: Sep 91977: Sep 241978: Sep 211979: Sep 151980: Sep 221981: Sep 171982: Sep 191983: Sep 171984: Sep 211985: Sep 191986: Sep 281987: Sep 171988: Sep 291989: Sep 101990: Oct 71991: Sep 191992: Sep 181993: Sep 141994: Sep 221995: Sep 201996: Sep 261997: Sep 251998: Oct 61999: Sep 132000: Sep 232001: Sep 92002: Sep 222003: Sep 152004: Oct 2

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

"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.