Last Frost Day

Frost history / Idaho Falls - Kifi, ID

Idaho Falls - Kifi, ID: frost dates by year

Last spring and first fall frost at NOAA station USC00104455, 1952 to 2025, measured from daily minimum temperatures.

Elevation 4,742 ft, 43.514, -112.013. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 21Sep 23
EarliestApr 19 (2025)Aug 25 (1992)
LatestJun 30 (1970)Oct 28 (2015)
Trend2.3 days earlier per decade2.6 days later per decade
Years with data6162

At 28°F (hard freeze) the median last spring date is May 6 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 29Jul 1419601970198019902000201020201953: May 251954: Jun 81955: Jun 41959: May 291960: May 241961: May 151962: Jun 71963: Apr 301965: May 271966: May 231967: May 131968: May 231969: May 11970: Jun 301971: May 171972: May 121974: May 311975: May 261976: Jun 261977: May 301978: May 311979: Jun 81982: May 291983: May 171986: May 231987: Apr 211988: May 201989: Jun 211990: Jun 131992: May 121993: Jun 121994: May 21995: Jun 71996: May 91997: May 91998: Jun 51999: Jun 92000: May 122001: May 212002: May 122003: May 202004: Apr 302005: Jun 82006: May 112007: May 232010: Jun 182011: May 52012: May 82013: May 22014: May 132015: May 112016: May 112017: May 202018: Jun 132019: Jun 92020: May 72021: May 102022: May 232023: Apr 282024: May 32025: Apr 19

First fall frost (32°F)

Aug 13Aug 28Sep 12Sep 27Oct 12Oct 27Nov 1119601970198019902000201020201952: Sep 141953: Oct 31954: Sep 191955: Sep 221959: Sep 221960: Oct 131961: Sep 141963: Oct 161964: Sep 31966: Oct 11967: Sep 131968: Sep 231969: Oct 31970: Sep 91971: Sep 151972: Sep 141973: Sep 171974: Sep 131975: Sep 191976: Sep 81979: Oct 31981: Sep 261982: Oct 21983: Sep 101984: Sep 241985: Sep 201986: Sep 211987: Sep 161988: Sep 121989: Sep 111990: Oct 81991: Sep 151992: Aug 251993: Sep 131994: Oct 31995: Sep 211996: Sep 71997: Oct 61998: Oct 41999: Sep 272000: Sep 232001: Sep 82002: Sep 222004: Sep 222005: Sep 182008: Oct 92010: Sep 72011: Oct 132012: Oct 42013: Oct 52014: Sep 122015: Oct 282016: Oct 62017: Sep 232018: Sep 252019: Sep 302020: Oct 222021: Oct 122022: Oct 142023: Oct 262024: Oct 202025: 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
2025Apr 19Oct 6Apr 19Oct 22
2024May 3Oct 20May 2Oct 25
2023Apr 28Oct 26Apr 28Oct 26
2022May 23Oct 14May 11Oct 24
2021May 10Oct 12May 9Oct 15
2020May 7Oct 22Apr 18Oct 23
2019Jun 9Sep 30May 3Oct 3
2018Jun 13Sep 25Apr 18Oct 13
2017May 20Sep 23May 20Oct 9
2016May 11Oct 6Apr 17Oct 12
2015May 11Oct 28Apr 15Nov 6
2014May 13Sep 12May 13Sep 12
2013May 2Oct 5May 2Oct 5
2012May 8Oct 4Apr 16Oct 4
2011May 5Oct 13May 2Oct 25
2010Jun 18Sep 7May 7Oct 13
2008no dataOct 9no dataOct 10
2007May 23no dataMay 6no data
2006May 11no dataMay 10no data
2005Jun 8Sep 18Apr 29Oct 5
2004Apr 30Sep 22Apr 11Oct 25
2003May 20no dataMay 20no data
2002May 12Sep 22May 9Oct 3
2001May 21Sep 8May 6Oct 5
2000May 12Sep 23Apr 30Sep 24
1999Jun 9Sep 27May 11Sep 28
1998Jun 5Oct 4Apr 27Oct 4
1997May 9Oct 6Apr 13Oct 12
1996May 9Sep 7May 5Sep 23
1995Jun 7Sep 21Jun 7Sep 21
1994May 2Oct 3May 2Oct 17
1993Jun 12Sep 13May 10Sep 22
1992May 12Aug 25Apr 25Oct 7
1991no dataSep 15no dataOct 5
1990Jun 13Oct 8May 9Oct 8
1989Jun 21Sep 11May 19Oct 5
1988May 20Sep 12May 3Sep 12
1987Apr 21Sep 16Apr 20Oct 10
1986May 23Sep 21May 23Sep 29
1985no dataSep 20no dataSep 23
1984no dataSep 24no dataSep 25
1983May 17Sep 10May 14Sep 20
1982May 29Oct 2May 6Oct 6
1981no dataSep 26no dataOct 1
1979Jun 8Oct 3May 10Oct 21
1978May 31no dataMay 26no data
1977May 30no dataApr 19no data
1976Jun 26Sep 8Apr 27Oct 7
1975May 26Sep 19May 26Oct 23
1974May 31Sep 13May 15Oct 5
1973no dataSep 17no dataOct 3
1972May 12Sep 14May 2Sep 25
1971May 17Sep 15Apr 27Sep 17
1970Jun 30Sep 9May 14Sep 15
1969May 1Oct 3Apr 30Oct 4
1968May 23Sep 23May 6Oct 8
1967May 13Sep 13May 13Oct 15
1966May 23Oct 1May 23Oct 10
1965May 27no dataMay 6no data
1964no dataSep 3no dataSep 27
1963Apr 30Oct 16Apr 24Oct 24
1962Jun 7no dataApr 30no data
1961May 15Sep 14May 3Sep 14
1960May 24Oct 13May 24Oct 15
1959May 29Sep 22May 6Sep 29
1955Jun 4Sep 22May 28Sep 22
1954Jun 8Sep 19May 4Sep 29
1953May 25Oct 3May 12Oct 3
1952no dataSep 14no dataOct 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.