Last Frost Day

Frost history / Fairfield, MT

Fairfield, MT: frost dates by year

Last spring and first fall frost at NOAA station USC00242857, 1951 to 2025, measured from daily minimum temperatures.

Elevation 3,983 ft, 47.615, -111.986. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 18Sep 22
EarliestApr 17 (1998)Aug 21 (1992)
LatestJun 13 (1969)Oct 23 (2023)
Trend1.1 days earlier per decade1.4 days later per decade
Years with data7171

At 28°F (hard freeze) the median last spring date is May 1 and the median first fall date is Oct 5.

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)

Mar 31Apr 15Apr 30May 15May 30Jun 14Jun 2919601970198019902000201020201951: Jun 61952: Apr 211953: May 231954: May 31955: May 171956: May 131957: May 231958: May 31959: May 231960: May 241961: May 171962: Jun 61963: May 221964: May 261965: Jun 71966: May 181967: May 261968: May 201969: Jun 131970: May 141971: May 211972: May 111973: May 131974: May 201975: May 211976: May 161977: May 191978: May 301979: May 201980: May 111981: May 51982: Jun 81983: May 141984: May 251985: May 61986: May 161987: May 211988: May 21989: May 291990: May 181991: May 41992: May 211993: Apr 271994: Apr 291995: May 261996: May 101997: Apr 281998: Apr 171999: May 122000: May 312002: Jun 102003: May 182004: May 232005: May 112006: May 42007: May 52009: Jun 82010: Jun 122011: Apr 302012: May 272013: May 42014: May 112015: May 92016: May 142018: May 112019: May 182020: May 122021: May 232022: May 222023: Apr 232024: May 8

First fall frost (32°F)

Aug 13Aug 28Sep 12Sep 27Oct 12Oct 27Nov 1119601970198019902000201020201951: Sep 241952: Oct 41953: Oct 211954: Sep 201955: Sep 211956: Sep 51957: Sep 181958: Sep 221959: Sep 171960: Sep 221961: Sep 21962: Sep 31963: Oct 201964: Sep 101965: Sep 51966: Sep 301967: Oct 151968: Sep 201969: Sep 151970: Sep 101971: Sep 201972: Sep 251973: Sep 141974: Sep 21975: Sep 191976: Sep 81977: Sep 241978: Sep 171979: Oct 91980: Sep 241981: Sep 241982: Sep 131983: Sep 181985: Sep 71986: Oct 11987: Oct 81988: Sep 101989: Sep 91990: Sep 291991: Sep 171992: Aug 211993: Sep 161994: Oct 21995: Sep 181996: Sep 221997: Oct 81999: Sep 262000: Sep 202001: Oct 12002: Sep 242003: Sep 162004: Sep 302005: Sep 272006: Oct 92007: Sep 202008: Oct 92009: Sep 282010: Sep 182011: Oct 142013: Sep 262014: Sep 92015: Sep 272016: Sep 122017: Sep 222018: Sep 302019: Sep 272020: Sep 72022: Oct 222023: Oct 232024: Sep 302025: Oct 5

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
2025no dataOct 5no dataOct 13
2024May 8Sep 30May 4Oct 18
2023Apr 23Oct 23Apr 22Oct 24
2022May 22Oct 22Apr 24Oct 23
2021May 23no dataMay 21no data
2020May 12Sep 7Apr 16Oct 16
2019May 18Sep 27Apr 30Sep 28
2018May 11Sep 30Apr 14Sep 30
2017no dataSep 22no dataOct 2
2016May 14Sep 12Apr 17Oct 8
2015May 9Sep 27Mar 24Oct 27
2014May 11Sep 9May 11Oct 27
2013May 4Sep 26Apr 30Oct 3
2012May 27no dataApr 16no data
2011Apr 30Oct 14Apr 29Oct 16
2010Jun 12Sep 18May 11Oct 16
2009Jun 8Sep 28May 3Oct 8
2008no dataOct 9no dataOct 9
2007May 5Sep 20Apr 20Oct 26
2006May 4Oct 9Apr 25Oct 13
2005May 11Sep 27May 1Oct 22
2004May 23Sep 30May 13Sep 30
2003May 18Sep 16May 18Oct 24
2002Jun 10Sep 24May 21Oct 1
2001no dataOct 1no dataOct 4
2000May 31Sep 20Apr 15Sep 21
1999May 12Sep 26May 10Sep 26
1998Apr 17no dataApr 15no data
1997Apr 28Oct 8Apr 12Oct 12
1996May 10Sep 22May 9Sep 22
1995May 26Sep 18May 12Sep 20
1994Apr 29Oct 2Apr 29Oct 29
1993Apr 27Sep 16Apr 12Sep 20
1992May 21Aug 21Apr 23Oct 12
1991May 4Sep 17May 2Oct 17
1990May 18Sep 29May 8Oct 5
1989May 29Sep 9Apr 29Oct 15
1988May 2Sep 10May 1Oct 17
1987May 21Oct 8Apr 19Oct 8
1986May 16Oct 1Apr 29Oct 10
1985May 6Sep 7Apr 26Sep 23
1984May 25no dataApr 30no data
1983May 14Sep 18May 13Sep 19
1982Jun 8Sep 13May 11Sep 15
1981May 5Sep 24Apr 14Oct 4
1980May 11Sep 24Apr 13Oct 10
1979May 20Oct 9Apr 25Oct 9
1978May 30Sep 17May 4Sep 17
1977May 19Sep 24May 18Oct 4
1976May 16Sep 8Apr 23Oct 15
1975May 21Sep 19Apr 30Oct 23
1974May 20Sep 2May 3Sep 27
1973May 13Sep 14May 13Sep 16
1972May 11Sep 25May 1Sep 25
1971May 21Sep 20Apr 27Sep 21
1970May 14Sep 10May 13Sep 11
1969Jun 13Sep 15May 8Sep 15
1968May 20Sep 20May 11Oct 3
1967May 26Oct 15May 13Oct 24
1966May 18Sep 30May 18Sep 30
1965Jun 7Sep 5May 18Sep 15
1964May 26Sep 10Apr 28Oct 4
1963May 22Oct 20May 19Oct 20
1962Jun 6Sep 3May 5Nov 7
1961May 17Sep 2May 7Sep 19
1960May 24Sep 22May 6Oct 19
1959May 23Sep 17May 14Sep 29
1958May 3Sep 22Apr 28Oct 9
1957May 23Sep 18Apr 17Sep 18
1956May 13Sep 5May 13Oct 9
1955May 17Sep 21Apr 29Sep 25
1954May 3Sep 20May 3Sep 29
1953May 23Oct 21May 13Oct 22
1952Apr 21Oct 4Apr 21Oct 4
1951Jun 6Sep 24May 29Sep 26

"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.