Last Frost Day

Frost history / Bozeman Gallatin Fld, MT

Bozeman Gallatin Fld, MT: frost dates by year

Last spring and first fall frost at NOAA station USW00024132, 1951 to 2024, measured from daily minimum temperatures.

Elevation 4,427 ft, 45.788, -111.161. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 31Sep 13
EarliestMay 4 (1972)Aug 23 (2015)
LatestJul 31 (1968)Oct 18 (1963)
Trend0.8 days earlier per decadelittle change (less than half a day per decade)
Years with data7373

At 28°F (hard freeze) the median last spring date is May 11 and the median first fall date is Sep 25.

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 14Jul 29Aug 1319601970198019902000201020201951: Jun 31952: Jun 231953: May 231954: Jun 181955: May 281956: May 131957: May 221958: May 131959: May 291960: Jun 211961: May 131962: Jun 71963: May 201964: May 51965: May 181966: Jun 131967: May 261968: Jul 311969: Jun 141970: Jun 131971: Jul 71972: May 41973: May 301974: Jun 71975: Jun 281976: May 261977: May 301978: May 301979: Jun 81980: May 131981: May 81982: May 311983: May 311984: Jun 21985: Jun 261986: May 231987: Jun 31988: Jun 301989: May 311990: Jun 121991: Jun 181992: Jun 41993: May 251994: Jun 91995: Jun 71996: Jun 201997: May 191998: Jun 51999: Jun 92000: Jun 12001: Jun 162002: May 252003: Jun 232004: May 252005: May 312006: May 302007: May 242008: Jun 112009: May 212010: May 142011: Jun 42012: Jun 72013: Jun 12015: May 112016: May 222017: May 262018: Jun 122019: May 192020: May 112021: Jun 112022: May 232023: May 102024: May 31

First fall frost (32°F)

Aug 13Aug 28Sep 12Sep 27Oct 12Oct 2719601970198019902000201020201951: Sep 41952: Sep 141953: Sep 201954: Sep 191955: Sep 211956: Sep 61957: Sep 101958: Sep 201959: Sep 21960: Sep 81961: Sep 131962: Sep 41963: Oct 181964: Sep 101965: Aug 301966: Sep 301967: Oct 41968: Sep 31969: Sep 41970: Sep 131971: Aug 241972: Sep 71973: Sep 171974: Sep 21975: Sep 121976: Aug 271977: Sep 91978: Sep 181979: Sep 111980: Sep 251981: Sep 221982: Sep 141983: Sep 101984: Sep 131985: Sep 201986: Sep 221987: Sep 171988: Sep 131989: Sep 71990: Sep 221991: Sep 181992: Aug 241993: Aug 301994: Sep 51995: Sep 201996: Sep 61997: Sep 171998: Sep 211999: Sep 72000: Sep 72001: Sep 202002: Sep 212003: Sep 142004: Sep 42005: Sep 122006: Sep 12007: Sep 102008: Sep 82009: Sep 92010: Oct 112011: Sep 42012: Aug 252013: Sep 272015: Aug 232016: Sep 252017: Sep 172018: Sep 212019: Sep 282020: Sep 82021: Sep 172022: Sep 102023: Oct 72024: Sep 22

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
2024May 31Sep 22May 24Oct 1
2023May 10Oct 7Apr 28Oct 24
2022May 23Sep 10May 21Oct 16
2021Jun 11Sep 17May 22Sep 30
2020May 11Sep 8May 8Oct 15
2019May 19Sep 28May 10Oct 3
2018Jun 12Sep 21Apr 25Oct 1
2017May 26Sep 17May 3Oct 3
2016May 22Sep 25May 2Oct 7
2015May 11Aug 23May 11Oct 16
2013Jun 1Sep 27May 2Oct 4
2012Jun 7Aug 25May 12Sep 12
2011Jun 4Sep 4May 5Sep 20
2010May 14Oct 11May 13Oct 12
2009May 21Sep 9May 21Oct 2
2008Jun 11Sep 8May 3Oct 8
2007May 24Sep 10Apr 22Oct 26
2006May 30Sep 1May 11Oct 10
2005May 31Sep 12May 3Oct 6
2004May 25Sep 4May 25Oct 6
2003Jun 23Sep 14May 20Sep 14
2002May 25Sep 21May 23Sep 22
2001Jun 16Sep 20May 30Oct 4
2000Jun 1Sep 7Apr 30Sep 20
1999Jun 9Sep 7May 11Sep 12
1998Jun 5Sep 21Apr 28Oct 4
1997May 19Sep 17May 19Sep 20
1996Jun 20Sep 6Jun 19Sep 6
1995Jun 7Sep 20May 23Sep 21
1994Jun 9Sep 5Apr 30Sep 22
1993May 25Aug 30May 8Sep 14
1992Jun 4Aug 24May 12Aug 25
1991Jun 18Sep 18May 5Sep 18
1990Jun 12Sep 22May 10Oct 7
1989May 31Sep 7May 24Sep 10
1988Jun 30Sep 13May 3Sep 19
1987Jun 3Sep 17May 3Sep 17
1986May 23Sep 22May 23Sep 23
1985Jun 26Sep 20May 12Sep 20
1984Jun 2Sep 13May 22Sep 24
1983May 31Sep 10May 14Sep 19
1982May 31Sep 14May 31Oct 6
1981May 8Sep 22Apr 15Oct 5
1980May 13Sep 25Apr 16Oct 9
1979Jun 8Sep 11May 30Sep 14
1978May 30Sep 18May 4Oct 2
1977May 30Sep 9May 29Oct 5
1976May 26Aug 27Apr 30Sep 8
1975Jun 28Sep 12May 26Sep 21
1974Jun 7Sep 2May 16Sep 13
1973May 30Sep 17May 12Oct 3
1972May 4Sep 7May 2Sep 21
1971Jul 7Aug 24Apr 27Sep 15
1970Jun 13Sep 13May 1Sep 13
1969Jun 14Sep 4May 8Sep 4
1968Jul 31Sep 3May 11Sep 22
1967May 26Oct 4May 11Oct 17
1966Jun 13Sep 30May 12Sep 30
1965May 18Aug 30May 18Sep 16
1964May 5Sep 10Apr 27Sep 11
1963May 20Oct 18Apr 25Oct 24
1962Jun 7Sep 4Apr 30Sep 8
1961May 13Sep 13May 13Sep 14
1960Jun 21Sep 8May 18Sep 8
1959May 29Sep 2May 12Sep 28
1958May 13Sep 20Apr 30Oct 2
1957May 22Sep 10Apr 27Oct 3
1956May 13Sep 6May 12Oct 1
1955May 28Sep 21May 9Sep 30
1954Jun 18Sep 19May 3Sep 19
1953May 23Sep 20May 14Sep 25
1952Jun 23Sep 14Apr 22Sep 14
1951Jun 3Sep 4Jun 3Sep 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.