Last Frost Day

Frost history / Mtn Home, ID

Mtn Home, ID: frost dates by year

Last spring and first fall frost at NOAA station USC00106174, 1951 to 2006, measured from daily minimum temperatures.

Elevation 3,140 ft, 43.126, -115.712. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 13Sep 24
EarliestApr 14 (1994)Aug 29 (1960)
LatestJun 18 (1973)Oct 30 (1988)
Trend1.6 days earlier per decade2.5 days later per decade
Years with data4747

At 28°F (hard freeze) the median last spring date is May 2 and the median first fall date is Oct 11.

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 29196019701980199020001951: May 281953: May 271954: Jun 21955: May 281956: May 131957: Apr 261958: May 131959: May 101961: May 71962: Jun 31963: Apr 231964: May 71965: May 251967: May 141968: May 161969: May 201970: May 311972: May 11973: Jun 181974: May 211975: May 261976: Apr 231977: May 51979: Jun 81981: May 71982: May 51983: May 121984: Jun 11985: May 131986: May 221987: Apr 211988: May 31989: May 191992: Apr 241993: May 81994: Apr 141995: Jun 61996: May 41997: May 21998: Jun 171999: May 142000: May 122001: Jun 132002: May 92003: May 192005: Apr 182006: May 2

First fall frost (32°F)

Aug 13Aug 28Sep 12Sep 27Oct 12Oct 27Nov 11196019701980199020001951: Sep 221953: Oct 31954: Sep 201955: Sep 221956: Sep 221957: Sep 201958: Sep 241960: Aug 291961: Sep 221962: Sep 301963: Oct 261964: Sep 201965: Sep 161967: Sep 131968: Sep 211969: Sep 41970: Sep 91971: Sep 161974: Oct 41975: Sep 271976: Sep 81977: Sep 221980: Sep 221981: Oct 41982: Oct 81983: Sep 211984: Sep 241985: Sep 291986: Sep 281987: Sep 271988: Oct 301989: Oct 161990: Oct 71991: Oct 181992: Sep 61993: Sep 211994: Oct 21996: Sep 191997: Oct 81998: Oct 41999: Sep 272000: Sep 232001: Oct 102002: Oct 22004: Oct 102005: Oct 42006: Sep 16

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
2006May 2Sep 16Apr 18Oct 17
2005Apr 18Oct 4Apr 14Oct 4
2004no dataOct 10no dataOct 31
2003May 19no dataMay 19no data
2002May 9Oct 2May 8Oct 11
2001Jun 13Oct 10May 3Oct 10
2000May 12Sep 23Mar 31Oct 22
1999May 14Sep 27May 11Sep 28
1998Jun 17Oct 4Apr 26Oct 5
1997May 2Oct 8May 2Oct 8
1996May 4Sep 19May 4Oct 17
1995Jun 6no dataApr 15no data
1994Apr 14Oct 2Apr 8Oct 22
1993May 8Sep 21Apr 19Oct 19
1992Apr 24Sep 6Apr 24Oct 16
1991no dataOct 18no dataOct 24
1990no dataOct 7no dataOct 11
1989May 19Oct 16May 19Oct 16
1988May 3Oct 30May 2Nov 7
1987Apr 21Sep 27Apr 21Oct 19
1986May 22Sep 28Apr 30Oct 12
1985May 13Sep 29Apr 26Oct 8
1984Jun 1Sep 24May 16Sep 25
1983May 12Sep 21Apr 26Nov 8
1982May 5Oct 8May 5Oct 10
1981May 7Oct 4Apr 13Oct 4
1980no dataSep 22no dataOct 22
1979Jun 8no dataApr 25no data
1977May 5Sep 22Apr 20Oct 1
1976Apr 23Sep 8Apr 19Oct 16
1975May 26Sep 27May 25Oct 23
1974May 21Oct 4May 16Oct 4
1973Jun 18no dataMay 11no data
1972May 1no dataMay 1no data
1971no dataSep 16no dataSep 27
1970May 31Sep 9May 11Sep 15
1969May 20Sep 4May 3Oct 5
1968May 16Sep 21May 8Oct 8
1967May 14Sep 13May 12Oct 24
1965May 25Sep 16May 7Sep 19
1964May 7Sep 20May 6Oct 17
1963Apr 23Oct 26Apr 21Oct 27
1962Jun 3Sep 30Apr 30Oct 7
1961May 7Sep 22May 6Sep 22
1960no dataAug 29no dataOct 13
1959May 10no dataMay 3no data
1958May 13Sep 24Apr 28Sep 24
1957Apr 26Sep 20Apr 26Oct 4
1956May 13Sep 22Apr 29Oct 22
1955May 28Sep 22May 15Sep 29
1954Jun 2Sep 20May 2Oct 1
1953May 27Oct 3May 11Oct 26
1951May 28Sep 22Apr 22Oct 16

"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.