Last Frost Day

Frost history / Valentine, MT

Valentine, MT: frost dates by year

Last spring and first fall frost at NOAA station USC00248498, 1985 to 2025, measured from daily minimum temperatures.

Elevation 2,905 ft, 47.339, -108.499. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 20Sep 21
EarliestApr 29 (2023)Aug 23 (2015)
LatestJun 26 (1989)Oct 12 (2010)
Trend1.8 days earlier per decade2.7 days later per decade
Years with data4141

At 28°F (hard freeze) the median last spring date is May 9 and the median first fall date is Oct 2.

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 1419902000201020201985: May 141986: May 171987: May 201988: May 201989: Jun 261990: May 171991: May 271992: May 251993: May 251994: May 91995: May 251996: May 111997: May 201998: Jun 61999: Jun 102000: May 142001: May 302002: May 242003: May 202004: May 252005: May 142006: May 112007: May 242008: May 112009: Jun 82010: May 302011: May 142012: May 252013: May 112014: Jun 72015: May 212016: May 152017: May 292018: May 12019: May 92020: May 142021: May 222022: Jun 12023: Apr 292024: May 202025: May 22

First fall frost (32°F)

Aug 13Aug 28Sep 12Sep 27Oct 12Oct 2719902000201020201985: Sep 231986: Sep 71987: Sep 121988: Sep 81989: Sep 111990: Sep 221991: Sep 181992: Aug 251993: Sep 141994: Sep 221995: Sep 211996: Sep 241997: Sep 171998: Oct 71999: Sep 142000: Sep 222001: Oct 32002: Sep 222003: Sep 142004: Sep 212005: Sep 122006: Oct 82007: Sep 142008: Sep 82009: Sep 282010: Oct 122011: Sep 212012: Oct 52013: Oct 42014: Sep 122015: Aug 232016: Sep 132017: Sep 242018: Sep 302019: Sep 302020: Sep 82021: Sep 172022: Sep 102023: Oct 62024: 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 22Oct 6May 2Oct 6
2024May 20Oct 1May 5Oct 13
2023Apr 29Oct 6Apr 28Oct 6
2022Jun 1Sep 10May 23Oct 16
2021May 22Sep 17May 11Sep 30
2020May 14Sep 8May 11Oct 1
2019May 9Sep 30May 9Oct 1
2018May 1Sep 30Apr 24Oct 4
2017May 29Sep 24Apr 29Oct 4
2016May 15Sep 13May 14Sep 13
2015May 21Aug 23May 18Oct 15
2014Jun 7Sep 12May 8Oct 3
2013May 11Oct 4May 11Oct 4
2012May 25Oct 5May 25Oct 5
2011May 14Sep 21May 2Sep 21
2010May 30Oct 12May 9Oct 12
2009Jun 8Sep 28May 2Sep 28
2008May 11Sep 8Apr 28Oct 9
2007May 24Sep 14Apr 14Sep 30
2006May 11Oct 8May 5Oct 10
2005May 14Sep 12May 3Sep 28
2004May 25Sep 21May 14Sep 22
2003May 20Sep 14Apr 10Sep 18
2002May 24Sep 22May 11Oct 2
2001May 30Oct 3May 30Oct 4
2000May 14Sep 22May 14Sep 22
1999Jun 10Sep 14May 12Oct 3
1998Jun 6Oct 7May 8Oct 12
1997May 20Sep 17May 19Oct 6
1996May 11Sep 24May 10Sep 24
1995May 25Sep 21May 22Sep 21
1994May 9Sep 22May 4Sep 22
1993May 25Sep 14Apr 25Sep 14
1992May 25Aug 25May 25Sep 18
1991May 27Sep 18May 5Sep 18
1990May 17Sep 22May 9Sep 22
1989Jun 26Sep 11Apr 30Sep 11
1988May 20Sep 8May 3Oct 4
1987May 20Sep 12Apr 20Oct 5
1986May 17Sep 7May 16Oct 11
1985May 14Sep 23May 14Sep 24

"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.