Last Frost Day

Frost history / Huntley Exp Stn, MT

Huntley Exp Stn, MT: frost dates by year

Last spring and first fall frost at NOAA station USC00244345, 1951 to 2025, measured from daily minimum temperatures.

Elevation 3,034 ft, 45.923, -108.245. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 14Sep 19
EarliestApr 24 (1978)Aug 17 (2002)
LatestJun 13 (1969)Oct 24 (1963)
Trend0.7 days earlier per decade0.9 days later per decade
Years with data7170

At 28°F (hard freeze) the median last spring date is May 3 and the median first fall date is Oct 3.

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 31953: May 231954: May 311955: May 71956: May 41957: Apr 281958: May 51959: May 291960: May 201961: May 81962: May 21963: May 221964: May 121965: Jun 81966: May 121967: May 141968: May 191969: Jun 131970: May 131971: May 121972: May 21973: May 241974: May 231975: May 251976: May 71977: May 161978: Apr 241979: Jun 81980: May 121981: May 121982: Jun 11983: Jun 11984: Jun 21985: May 141986: May 171987: May 61988: May 31989: May 261990: Jun 21991: May 51992: May 31994: May 41995: May 231998: May 101999: May 172000: May 142001: May 112002: May 232003: May 202004: May 252005: May 132006: May 142007: May 242008: Jun 112009: May 212010: May 142011: May 52012: May 262013: Jun 72014: May 92015: May 112016: May 142017: May 202018: Apr 252019: May 102020: May 92021: May 62022: May 242023: Apr 282024: May 52025: May 7

First fall frost (32°F)

Jul 29Aug 13Aug 28Sep 12Sep 27Oct 12Oct 27Nov 1119601970198019902000201020201951: Sep 141952: Sep 151953: Sep 211954: Sep 211955: Sep 221956: Sep 231957: Oct 51958: Sep 271959: Sep 101960: Sep 91961: Sep 131962: Sep 41963: Oct 241964: Sep 111965: Sep 161966: Sep 301967: Oct 171968: Oct 31969: Oct 51970: Sep 121971: Sep 151972: Sep 211973: Sep 141974: Sep 21975: Sep 121976: Sep 81977: Sep 241978: Sep 201979: Sep 141980: Sep 41981: Oct 11982: Sep 141983: Sep 191985: Sep 201986: Oct 111987: Sep 181988: Sep 191989: Sep 111990: Sep 221991: Sep 181993: Sep 141994: Sep 221997: Sep 171998: Oct 111999: Sep 132000: Sep 222001: Oct 52002: Aug 172003: Sep 142005: Sep 222006: Sep 32007: Sep 142008: Sep 82009: Sep 222010: Oct 122011: Sep 212012: Sep 122013: Oct 52014: Sep 122015: Oct 152016: Oct 62017: Sep 172018: Sep 212019: Oct 12020: Sep 92021: Sep 172022: Oct 162023: Oct 62024: Oct 12025: Oct 19

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