Last Frost Day

Frost history / Big Timber, MT

Big Timber, MT: frost dates by year

Last spring and first fall frost at NOAA station USC00240780, 1951 to 2025, measured from daily minimum temperatures.

Elevation 4,100 ft, 45.833, -109.951. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 14Sep 19
EarliestApr 24 (1978)Aug 24 (1992)
LatestJun 14 (1969)Oct 26 (1963)
Trendlittle change (less than half a day per decade)1.5 days later per decade
Years with data6566

At 28°F (hard freeze) the median last spring date is May 3 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)

Apr 15Apr 30May 15May 30Jun 14Jun 2919601970198019902000201020201951: Jun 41952: May 101953: May 231954: May 291955: May 71956: May 41957: Apr 271958: Apr 291959: May 291960: May 201961: May 131962: Jun 51963: May 211964: May 121965: May 81966: May 191969: Jun 141970: May 11971: May 111972: May 71974: May 231976: May 161977: May 221978: Apr 241979: Jun 81980: May 121981: May 121982: May 311983: May 151984: Jun 21985: May 141986: May 171987: May 201988: May 201989: May 191990: May 131991: May 51992: May 121993: May 31994: May 42001: May 82002: May 232003: May 202004: May 252005: May 122006: May 112007: May 242008: May 32009: May 212010: May 232011: May 52012: May 262013: May 92014: May 82015: May 112016: May 122017: May 192018: Apr 272019: May 192020: May 82021: May 302022: May 232023: May 102024: May 232025: May 6

First fall frost (32°F)

Aug 13Aug 28Sep 12Sep 27Oct 12Oct 27Nov 1119601970198019902000201020201951: Sep 151952: Oct 41953: Sep 211954: Sep 301955: Oct 21956: Sep 31957: Sep 191958: Sep 161959: Sep 101960: Sep 81961: Sep 141962: Sep 41963: Oct 261964: Sep 121965: Sep 151966: Sep 301967: Oct 181968: Oct 31969: Sep 151970: Sep 121971: Sep 181972: Sep 201973: Sep 141974: Sep 131975: Sep 121976: Sep 91977: Sep 91978: Oct 31979: Sep 141980: Sep 261981: Oct 51982: Sep 141983: Sep 181984: Sep 131985: Sep 231986: Oct 111987: Sep 181988: Sep 111989: Sep 111990: Sep 291991: Sep 181992: Aug 241994: Sep 222003: Sep 142004: Oct 22005: Oct 42006: Oct 92007: Sep 142008: Sep 242009: Sep 282010: Oct 162011: Sep 212012: Sep 122013: Oct 32014: Sep 112015: Oct 162016: Oct 62017: Sep 252018: Sep 212019: Sep 292020: Sep 92021: Sep 172022: Oct 132023: Oct 152024: Oct 12025: Oct 6

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

"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.