Last Frost Day

Frost history / Medicine Bow, WY

Medicine Bow, WY: frost dates by year

Last spring and first fall frost at NOAA station USC00486120, 1951 to 2013, measured from daily minimum temperatures.

Elevation 6,635 ft, 41.897, -106.206. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianJun 5Sep 5
EarliestMay 13 (1961)Aug 19 (1954)
LatestJul 21 (1999)Sep 28 (1998)
Trendlittle change (less than half a day per decade)1.3 days later per decade
Years with data5049

At 28°F (hard freeze) the median last spring date is May 16 and the median first fall date is Sep 14.

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 291960197019801990200020101951: Jun 41952: May 271953: Jun 251954: Jun 291955: Jun 21956: May 171957: Jun 231958: May 161959: Jun 21960: Jun 231961: May 131962: Jun 161963: May 261964: Jun 31965: Jun 61966: Jun 131968: Jul 11969: Jun 131970: Jun 131971: May 301972: Jun 191973: Jul 211975: Jun 191976: Jun 301977: May 291978: Jun 21981: May 201987: Jun 41988: May 231989: Jun 221990: Jun 221991: May 141992: May 171993: Jul 71994: Jun 101995: Jun 111996: Jun 21997: May 201998: Jun 71999: Jul 212000: Jun 22001: Jun 132002: May 252003: Jun 82004: Jun 12005: Jun 112006: May 302010: May 312011: Jun 102013: Jun 4

First fall frost (32°F)

Aug 13Aug 28Sep 12Sep 27Oct 121960197019801990200020101951: Sep 101952: Sep 21953: Sep 31954: Aug 191955: Sep 121956: Aug 311957: Sep 111958: Sep 161959: Sep 21960: Aug 191961: Sep 111962: Aug 281963: Sep 251964: Aug 201965: Sep 11966: Aug 251969: Sep 231970: Sep 101971: Sep 151972: Sep 131974: Aug 221975: Sep 11976: Aug 271977: Sep 91979: Sep 131980: Aug 201986: Sep 81987: Sep 51988: Sep 41989: Aug 261990: Sep 221991: Sep 151992: Aug 271994: Sep 51996: Sep 71997: Sep 241998: Sep 281999: Sep 52000: Sep 72001: Sep 92002: Sep 232003: Sep 132004: Aug 282005: Aug 312006: Sep 32008: Sep 22010: Sep 32011: Sep 212013: Sep 20

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
2013Jun 4Sep 20May 7Sep 20
2011Jun 10Sep 21May 19Sep 22
2010May 31Sep 3May 15Sep 3
2008no dataSep 2no dataOct 12
2006May 30Sep 3May 30Sep 25
2005Jun 11Aug 31May 12Sep 13
2004Jun 1Aug 28May 14Sep 16
2003Jun 8Sep 13May 20Sep 18
2002May 25Sep 23May 25Sep 23
2001Jun 13Sep 9May 21Sep 10
2000Jun 2Sep 7May 13Sep 7
1999Jul 21Sep 5Jul 21Sep 9
1998Jun 7Sep 28Jun 7Oct 5
1997May 20Sep 24May 12Oct 10
1996Jun 2Sep 7May 21Sep 7
1995Jun 11no dataMay 14no data
1994Jun 10Sep 5May 2Sep 16
1993Jul 7no dataMay 11no data
1992May 17Aug 27May 4Aug 27
1991May 14Sep 15May 5Sep 16
1990Jun 22Sep 22May 17Sep 23
1989Jun 22Aug 26Jun 22Sep 14
1988May 23Sep 4May 4Sep 29
1987Jun 4Sep 5Apr 24Sep 18
1986no dataSep 8no dataSep 17
1981May 20no dataMay 14no data
1980no dataAug 20no dataSep 1
1979no dataSep 13no dataSep 14
1978Jun 2no dataMay 9no data
1977May 29Sep 9May 29Sep 10
1976Jun 30Aug 27Jun 14Aug 28
1975Jun 19Sep 1Jun 11Sep 19
1974no dataAug 22no dataSep 3
1973Jul 21no dataJun 4no data
1972Jun 19Sep 13May 4Sep 21
1971May 30Sep 15May 19Sep 15
1970Jun 13Sep 10Jun 5Sep 10
1969Jun 13Sep 23Jun 2Oct 3
1968Jul 1no dataMay 27no data
1966Jun 13Aug 25Jun 6Oct 1
1965Jun 6Sep 1Jun 6Sep 1
1964Jun 3Aug 20Jun 2Aug 30
1963May 26Sep 25May 20Sep 25
1962Jun 16Aug 28May 15Sep 9
1961May 13Sep 11May 8Sep 14
1960Jun 23Aug 19May 7Sep 9
1959Jun 2Sep 2May 7Sep 10
1958May 16Sep 16May 5Sep 16
1957Jun 23Sep 11May 2Sep 11
1956May 17Aug 31May 14Sep 1
1955Jun 2Sep 12May 20Sep 28
1954Jun 29Aug 19Jun 8Sep 19
1953Jun 25Sep 3May 6Sep 5
1952May 27Sep 2May 11Sep 2
1951Jun 4Sep 10Jun 3Sep 13

"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.