Last Frost Day

Frost history / Powell, ID

Powell, ID: frost dates by year

Last spring and first fall frost at NOAA station USC00107320, 1963 to 2025, measured from daily minimum temperatures.

Elevation 3,530 ft, 46.510, -114.711. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianJun 11Sep 8
EarliestMay 8 (2025)Aug 17 (1969)
LatestJul 26 (2004)Oct 12 (2010)
Trend2.3 days earlier per decade1.6 days later per decade
Years with data4943

At 28°F (hard freeze) the median last spring date is May 14 and the median first fall date is Sep 22.

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 30May 15May 30Jun 14Jun 29Jul 14Jul 29Aug 131970198019902000201020201963: Jun 231964: May 261965: Jun 281966: May 241967: Jun 41968: May 311969: Jun 151971: Jul 81972: May 281973: Jul 21974: Jun 101975: Jun 111976: Jun 281977: Jul 81978: Jun 201979: Jul 41980: May 261981: Jun 251982: Jun 11983: Jun 141984: Jun 21985: Jun 271986: Jun 271987: Jun 231988: Jun 11989: May 241990: Jun 51991: Jun 191992: Jun 41993: May 241994: Jun 111995: May 281996: Jun 201997: Jun 231998: Jun 42000: Jun 242001: Jun 162002: Jun 82003: May 212004: Jul 262005: Jun 132006: May 312007: Jun 262008: Jun 152009: May 222010: May 242011: Jun 42012: Jun 72025: May 8

First fall frost (32°F)

Jul 29Aug 13Aug 28Sep 12Sep 27Oct 12Oct 271970198019902000201020201963: Aug 281964: Sep 101965: Aug 311966: Sep 301967: Sep 131968: Sep 221969: Aug 171970: Sep 121971: Aug 241972: Sep 71973: Sep 11974: Sep 21975: Aug 301976: Sep 81977: Sep 91978: Sep 171979: Sep 111980: Aug 291981: Sep 41982: Sep 151984: Sep 131985: Sep 11986: Sep 121987: Sep 171988: Sep 121989: Sep 41990: Oct 11991: Sep 121992: Aug 251993: Aug 251995: Sep 211996: Aug 191997: Sep 202004: Sep 22005: Aug 312007: Sep 82008: Sep 52009: Sep 92010: Oct 122011: Sep 42012: Aug 252024: Oct 12025: Sep 24

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 8Sep 24May 7Oct 19
2024no dataOct 1no dataOct 1
2012Jun 7Aug 25May 12Sep 12
2011Jun 4Sep 4May 3Oct 19
2010May 24Oct 12May 13Oct 13
2009May 22Sep 9May 21Sep 28
2008Jun 15Sep 5May 13Oct 9
2007Jun 26Sep 8Apr 21Sep 30
2006May 31no dataMay 13no data
2005Jun 13Aug 31May 1Sep 22
2004Jul 26Sep 2Jul 26Sep 25
2003May 21no dataMay 11no data
2002Jun 8no dataMay 12no data
2001Jun 16no dataMay 30no data
2000Jun 24no dataMay 15no data
1998Jun 4no dataApr 27no data
1997Jun 23Sep 20May 21Oct 16
1996Jun 20Aug 19May 9Sep 24
1995May 28Sep 21May 14Sep 21
1994Jun 11no dataMay 29no data
1993May 24Aug 25May 3Aug 25
1992Jun 4Aug 25May 22Aug 25
1991Jun 19Sep 12Jun 16Sep 16
1990Jun 5Oct 1May 10Oct 9
1989May 24Sep 4May 13Sep 12
1988Jun 1Sep 12May 20Sep 12
1987Jun 23Sep 17May 22Sep 17
1986Jun 27Sep 12May 23Sep 23
1985Jun 27Sep 1May 14Sep 23
1984Jun 2Sep 13May 8Sep 13
1983Jun 14no dataJun 14no data
1982Jun 1Sep 15May 20Sep 15
1981Jun 25Sep 4May 9Sep 24
1980May 26Aug 29May 12Aug 29
1979Jul 4Sep 11May 3Oct 1
1978Jun 20Sep 17Apr 24Sep 17
1977Jul 8Sep 9May 30Oct 4
1976Jun 28Sep 8May 27Sep 9
1975Jun 11Aug 30May 26Oct 23
1974Jun 10Sep 2May 19Sep 13
1973Jul 2Sep 1Jun 11Sep 16
1972May 28Sep 7May 26Sep 26
1971Jul 8Aug 24Jul 7Sep 14
1970no dataSep 12no dataSep 12
1969Jun 15Aug 17May 5Sep 4
1968May 31Sep 22May 4Oct 2
1967Jun 4Sep 13May 26Oct 7
1966May 24Sep 30May 19Oct 9
1965Jun 28Aug 31May 26Sep 16
1964May 26Sep 10May 26Sep 19
1963Jun 23Aug 28Apr 25Aug 28

"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.