Last Frost Day

Frost history / Neihart 8 Nnw, MT

Neihart 8 Nnw, MT: frost dates by year

Last spring and first fall frost at NOAA station USC00246008, 1967 to 2004, measured from daily minimum temperatures.

Elevation 5,230 ft, 47.041, -110.776. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianJun 15Sep 7
EarliestMay 19 (1997)Aug 3 (1978)
LatestJul 19 (1972)Sep 28 (1990)
Trend3.4 days earlier per decade2.2 days later per decade
Years with data3638

At 28°F (hard freeze) the median last spring date is May 22 and the median first fall date is Sep 17.

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 2919701980199020001968: Jun 141969: Jun 161970: Jun 111972: Jul 191973: Jul 21974: Jun 91975: Jun 171976: Jun 271977: Jul 81978: Jun 201979: Jun 91980: Jun 71981: Jul 81982: Jul 171983: May 311984: Jun 101985: Jun 261986: May 241987: Jun 231988: May 211989: Jun 41990: May 201991: Jun 181992: Jun 61993: Jul 11994: Jun 151995: Jun 101996: May 301997: May 191998: Jun 91999: Jul 162000: Jun 22001: Jun 162002: Jun 132003: Jun 252004: Jun 16

First fall frost (32°F)

Jul 29Aug 13Aug 28Sep 12Sep 27Oct 1219701980199020001967: Sep 121968: Sep 31969: Aug 301970: Sep 91971: Sep 141972: Sep 71973: Sep 131974: Aug 311975: Aug 241976: Aug 271977: Aug 111978: Aug 31979: Sep 111980: Aug 211981: Aug 311982: Sep 111983: Sep 61984: Sep 131985: Aug 171986: Sep 71987: Aug 121988: Sep 111989: Sep 71990: Sep 281991: Sep 181992: Aug 221993: Sep 131994: Sep 111995: Sep 191996: Sep 171997: Sep 191998: Sep 211999: Sep 12000: Sep 202001: Sep 72002: Aug 32003: Sep 142004: Sep 3

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
2004Jun 16Sep 3May 25Oct 1
2003Jun 25Sep 14May 20Sep 17
2002Jun 13Aug 3May 23Aug 3
2001Jun 16Sep 7May 30Oct 2
2000Jun 2Sep 20May 14Sep 21
1999Jul 16Sep 1May 10Sep 12
1998Jun 9Sep 21Jun 4Sep 21
1997May 19Sep 19May 19Sep 20
1996May 30Sep 17May 10Sep 23
1995Jun 10Sep 19May 24Sep 21
1994Jun 15Sep 11Apr 30Oct 3
1993Jul 1Sep 13Jun 3Sep 17
1992Jun 6Aug 22May 17Aug 25
1991Jun 18Sep 18May 5Sep 18
1990May 20Sep 28May 11Oct 3
1989Jun 4Sep 7May 30Sep 10
1988May 21Sep 11May 19Sep 12
1987Jun 23Aug 12May 20Oct 9
1986May 24Sep 7May 23Sep 7
1985Jun 26Aug 17May 16Sep 23
1984Jun 10Sep 13Jun 2Sep 13
1983May 31Sep 6May 31Sep 10
1982Jul 17Sep 11May 31Sep 11
1981Jul 8Aug 31Jun 18Sep 22
1980Jun 7Aug 21May 15Sep 22
1979Jun 9Sep 11Jun 8Oct 3
1978Jun 20Aug 3May 4Sep 17
1977Jul 8Aug 11May 30Sep 9
1976Jun 27Aug 27May 21Sep 7
1975Jun 17Aug 24May 9Sep 20
1974Jun 9Aug 31Jun 7Sep 2
1973Jul 2Sep 13Jun 18Sep 14
1972Jul 19Sep 7Jul 4Sep 7
1971no dataSep 14no dataSep 14
1970Jun 11Sep 9May 14Sep 10
1969Jun 16Aug 30Jun 14Sep 15
1968Jun 14Sep 3May 20Sep 17
1967no dataSep 12no dataOct 15

"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.