Last Frost Day

Frost history / Martinsdale 3 Nnw, MT

Martinsdale 3 Nnw, MT: frost dates by year

Last spring and first fall frost at NOAA station USC00245387, 1951 to 2011, measured from daily minimum temperatures.

Elevation 4,800 ft, 46.500, -110.338. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianJun 11Sep 3
EarliestMay 14 (1956)Aug 5 (1980)
LatestJul 31 (1968)Sep 22 (2000)
Trend1.8 days earlier per decadelittle change (less than half a day per decade)
Years with data4951

At 28°F (hard freeze) the median last spring date is May 21 and the median first fall date is Sep 16.

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 131960197019801990200020101951: Jul 111952: May 311953: Jun 211954: Jun 181955: Jun 91956: May 141957: May 241958: Jun 251959: Jun 21960: Jun 231961: May 191964: Jun 21965: Jun 281966: Jun 261967: May 271968: Jul 311969: Jun 151970: Jun 11971: Jul 301972: Jul 41973: Jul 21974: Jun 111975: Jun 171976: Jul 281986: May 241987: Jun 31988: May 231989: Jun 261990: Jun 141991: Jun 181992: Jun 61993: May 251994: Jun 151995: Jun 101996: May 211997: May 201998: Jun 61999: Jun 262000: May 192001: Jun 162002: May 252004: Jun 162005: May 312006: May 282007: Jun 262008: Jul 122009: Jun 92010: Jun 122011: May 19

First fall frost (32°F)

Jul 29Aug 13Aug 28Sep 12Sep 271960197019801990200020101951: Sep 51952: Sep 211953: Sep 201954: Sep 211955: Sep 111956: Sep 31957: Sep 181958: Sep 31959: Sep 21960: Aug 261961: Sep 131963: Sep 151964: Aug 251965: Aug 291966: Aug 221967: Aug 261968: Sep 31969: Aug 71970: Aug 91971: Aug 251972: Sep 11973: Sep 141974: Aug 311975: Aug 91977: Aug 111980: Aug 51986: Sep 121987: Aug 171988: Aug 281989: Sep 71990: Sep 141991: Sep 181992: Aug 241993: Aug 301994: Sep 21995: Sep 191996: Sep 61997: Sep 201998: Sep 201999: Sep 82000: Sep 222001: Sep 212003: Aug 302004: Sep 32005: Sep 12006: Sep 12007: Sep 102008: Sep 42009: Sep 92010: Aug 242011: Sep 2

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
2011May 19Sep 2May 19Sep 4
2010Jun 12Aug 24May 21Oct 12
2009Jun 9Sep 9May 22Sep 28
2008Jul 12Sep 4May 5Sep 8
2007Jun 26Sep 10May 24Sep 10
2006May 28Sep 1May 11Sep 2
2005May 31Sep 1May 31Sep 12
2004Jun 16Sep 3May 25Oct 4
2003no dataAug 30no dataSep 18
2002May 25no dataMay 23no data
2001Jun 16Sep 21May 21Oct 5
2000May 19Sep 22May 15Sep 22
1999Jun 26Sep 8Jun 26Sep 13
1998Jun 6Sep 20May 19Sep 22
1997May 20Sep 20May 20Sep 20
1996May 21Sep 6May 10Sep 18
1995Jun 10Sep 19May 24Sep 21
1994Jun 15Sep 2May 4Sep 22
1993May 25Aug 30May 3Sep 14
1992Jun 6Aug 24May 25Aug 25
1991Jun 18Sep 18May 6Sep 18
1990Jun 14Sep 14May 12Sep 23
1989Jun 26Sep 7May 26Sep 11
1988May 23Aug 28May 20Sep 19
1987Jun 3Aug 17Jun 3Sep 18
1986May 24Sep 12May 17Sep 13
1980no dataAug 5no dataAug 30
1977no dataAug 11no dataSep 9
1976Jul 28no dataJun 25no data
1975Jun 17Aug 9May 26Sep 12
1974Jun 11Aug 31May 23Sep 2
1973Jul 2Sep 14Jun 11Sep 15
1972Jul 4Sep 1May 4Sep 7
1971Jul 30Aug 25May 14Sep 17
1970Jun 1Aug 9May 4Sep 12
1969Jun 15Aug 7Jun 15Aug 30
1968Jul 31Sep 3May 20Oct 3
1967May 27Aug 26May 26Sep 23
1966Jun 26Aug 22Jun 13Aug 23
1965Jun 28Aug 29Jun 8Sep 16
1964Jun 2Aug 25May 26Sep 4
1963no dataSep 15no dataOct 24
1961May 19Sep 13May 16Sep 13
1960Jun 23Aug 26May 18Sep 8
1959Jun 2Sep 2May 23Sep 10
1958Jun 25Sep 3Jun 25Sep 16
1957May 24Sep 18Apr 27Sep 19
1956May 14Sep 3May 4Sep 4
1955Jun 9Sep 11May 7Sep 23
1954Jun 18Sep 21May 29Sep 21
1953Jun 21Sep 20May 23Sep 25
1952May 31Sep 21Apr 23Oct 2
1951Jul 11Sep 5Jun 4Sep 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.