Last Frost Day

Frost history / Koosharem, UT

Koosharem, UT: frost dates by year

Last spring and first fall frost at NOAA station USC00424764, 1952 to 2007, measured from daily minimum temperatures.

Elevation 6,930 ft, 38.509, -111.884. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianJun 16Sep 11
EarliestMay 13 (1986)Aug 12 (1985)
LatestJul 6 (1982)Oct 2 (1990)
Trendlittle change (less than half a day per decade)little change (less than half a day per decade)
Years with data4334

At 28°F (hard freeze) the median last spring date is Jun 2 and the median first fall date is Sep 20.

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 14196019701980199020001953: Jun 31954: Jun 81955: Jun 291957: Jun 221958: Jun 151959: Jun 21960: May 281962: Jun 171963: Jun 91964: Jun 231965: Jun 261966: Jun 81967: Jun 111968: Jun 301969: Jun 251970: Jun 301971: Jun 61972: May 241973: Jun 201974: Jun 101975: Jun 261976: Jun 241977: May 291978: Jun 11979: Jun 201980: Jun 221981: Jun 161982: Jul 61983: Jun 141984: Jun 121985: Jun 281986: May 131990: Jun 21991: Jun 221992: Jul 21993: Jul 51995: Jul 41997: May 262000: Jun 22001: Jun 152003: Jun 252006: Jun 162007: Jun 8

First fall frost (32°F)

Jul 29Aug 13Aug 28Sep 12Sep 27Oct 12196019701980199020001952: Sep 111953: Sep 41954: Sep 161955: Sep 201956: Sep 221957: Sep 11958: Sep 141959: Sep 161960: Aug 171961: Sep 31962: Aug 241965: Sep 91966: Sep 151967: Sep 131969: Sep 221970: Sep 101971: Sep 41972: Sep 71974: Aug 211975: Aug 281976: Sep 181977: Aug 271978: Aug 151979: Sep 131980: Aug 201981: Sep 261982: Sep 121983: Sep 201984: Sep 21985: Aug 121990: Oct 22005: Aug 312006: Sep 172007: Sep 18

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
2007Jun 8Sep 18Jun 8Sep 25
2006Jun 16Sep 17May 29Sep 17
2005no dataAug 31no dataSep 15
2003Jun 25no dataMay 6no data
2001Jun 15no dataJun 15no data
2000Jun 2no dataJun 2no data
1997May 26no dataMay 26no data
1995Jul 4no dataMay 27no data
1993Jul 5no dataMay 10no data
1992Jul 2no dataApr 25no data
1991Jun 22no dataMay 20no data
1990Jun 2Oct 2Jun 2Oct 2
1986May 13no dataMay 13no data
1985Jun 28Aug 12Jun 26Sep 12
1984Jun 12Sep 2Jun 11Sep 25
1983Jun 14Sep 20Jun 14Sep 20
1982Jul 6Sep 12Jun 6Sep 12
1981Jun 16Sep 26Jun 16Sep 26
1980Jun 22Aug 20May 29Sep 22
1979Jun 20Sep 13Jun 18Oct 6
1978Jun 1Aug 15Jun 1Sep 12
1977May 29Aug 27May 21Sep 18
1976Jun 24Sep 18Jun 15Oct 4
1975Jun 26Aug 28Jun 26Sep 21
1974Jun 10Aug 21Jun 9Sep 12
1973Jun 20no dataJun 19no data
1972May 24Sep 7May 23Sep 30
1971Jun 6Sep 4Jun 6Sep 4
1970Jun 30Sep 10May 17Sep 15
1969Jun 25Sep 22Apr 29Oct 3
1968Jun 30no dataJun 30no data
1967Jun 11Sep 13May 16Sep 13
1966Jun 8Sep 15Jun 2Sep 15
1965Jun 26Sep 9Jun 4Sep 9
1964Jun 23no dataJun 18no data
1963Jun 9no dataMay 13no data
1962Jun 17Aug 24Jun 17Aug 31
1961no dataSep 3no dataSep 4
1960May 28Aug 17May 25Oct 2
1959Jun 2Sep 16Jun 1Sep 25
1958Jun 15Sep 14May 15Sep 25
1957Jun 22Sep 1Jun 17Sep 11
1956no dataSep 22no dataSep 22
1955Jun 29Sep 20Jun 29Sep 20
1954Jun 8Sep 16Jun 7Sep 21
1953Jun 3Sep 4May 30Oct 3
1952no dataSep 11no dataSep 11

"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.