Last Frost Day

Frost history / Grant, CO

Grant, CO: frost dates by year

Last spring and first fall frost at NOAA station USC00053530, 1964 to 2025, measured from daily minimum temperatures.

Elevation 8,675 ft, 39.461, -105.679. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianJun 17Sep 11
EarliestMay 21 (2000)Aug 1 (1965)
LatestJul 13 (1987)Oct 3 (2015)
Trend2.3 days earlier per decade3.3 days later per decade
Years with data6060

At 28°F (hard freeze) the median last spring date is May 28 and the median first fall date is Sep 19.

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)

May 15May 30Jun 14Jun 29Jul 14Jul 291970198019902000201020201964: Jun 231965: Jun 271966: Jun 141967: Jun 241968: Jul 11969: Jun 301970: Jun 161971: Jun 111972: Jul 51973: Jun 211974: Jun 121975: Jun 261976: Jul 31977: May 281978: Jun 271979: Jun 211980: Jun 171981: Jun 181982: Jun 201983: Jun 161984: Jun 231986: Jun 111987: Jul 131988: Jun 21989: Jun 221990: Jun 131991: Jun 231992: Jun 171993: Jul 71994: Jul 71995: Jun 241996: Jun 11997: Jun 81998: Jun 192000: May 212001: Jun 142002: Jun 52003: Jun 262004: Jun 222005: Jun 152006: May 292007: Jun 152008: Jun 122009: Jun 122010: Jun 182011: Jun 92012: Jun 112013: May 312014: Jun 192015: Jun 32016: May 302017: Jun 132018: Jun 252019: Jun 252020: Jul 12021: Jun 12022: Jun 152023: Jun 242024: May 312025: May 27

First fall frost (32°F)

Jul 14Jul 29Aug 13Aug 28Sep 12Sep 27Oct 121970198019902000201020201964: Aug 211965: Aug 11966: Sep 41967: Sep 131968: Aug 151969: Sep 181970: Sep 41971: Sep 41972: Sep 131973: Sep 41974: Aug 101975: Aug 251976: Sep 11977: Sep 141978: Aug 151979: Sep 131980: Aug 41981: Sep 181982: Sep 131983: Sep 121985: Sep 121986: Sep 111988: Sep 41989: Sep 91990: Sep 201991: Sep 141992: Aug 251993: Sep 31994: Sep 51995: Sep 111996: Aug 301997: Sep 231998: Sep 211999: Sep 42000: Sep 232001: Sep 92002: Sep 192003: Sep 112004: Aug 282005: Sep 132006: Sep 122007: Sep 112008: Sep 42009: Aug 92010: Sep 72011: Sep 222012: Sep 142013: Sep 242014: Sep 122015: Oct 32016: Sep 92017: Sep 62018: Sep 212019: Sep 212020: Sep 82021: Sep 212022: Sep 132023: Sep 162024: Sep 192025: Sep 17

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
2025May 27Sep 17May 22Oct 5
2024May 31Sep 19May 24Oct 18
2023Jun 24Sep 16May 8Oct 5
2022Jun 15Sep 13May 31Oct 8
2021Jun 1Sep 21May 25Sep 21
2020Jul 1Sep 8May 27Sep 8
2019Jun 25Sep 21May 30Sep 21
2018Jun 25Sep 21May 4Oct 7
2017Jun 13Sep 6May 28Oct 9
2016May 30Sep 9May 26Sep 24
2015Jun 3Oct 3May 25Oct 28
2014Jun 19Sep 12Jun 15Sep 12
2013May 31Sep 24May 23Oct 4
2012Jun 11Sep 14May 14Sep 28
2011Jun 9Sep 22May 20Sep 22
2010Jun 18Sep 7May 31Oct 13
2009Jun 12Aug 9May 2Sep 22
2008Jun 12Sep 4Jun 12Sep 23
2007Jun 15Sep 11Jun 8Sep 25
2006May 29Sep 12May 12Sep 17
2005Jun 15Sep 13May 15Sep 17
2004Jun 22Aug 28Jun 1Aug 29
2003Jun 26Sep 11May 21Sep 14
2002Jun 5Sep 19May 26Sep 19
2001Jun 14Sep 9May 21Oct 4
2000May 21Sep 23May 14Sep 24
1999no dataSep 4no dataSep 14
1998Jun 19Sep 21Jun 6Oct 5
1997Jun 8Sep 23May 11Oct 8
1996Jun 1Aug 30May 5Sep 18
1995Jun 24Sep 11Jun 9Sep 20
1994Jul 7Sep 5May 4Sep 16
1993Jul 7Sep 3Jun 3Sep 8
1992Jun 17Aug 25Jun 2Aug 27
1991Jun 23Sep 14May 13Sep 16
1990Jun 13Sep 20Jun 2Oct 5
1989Jun 22Sep 9May 20Sep 9
1988Jun 2Sep 4May 22Sep 15
1987Jul 13no dataMay 28no data
1986Jun 11Sep 11Jun 11Sep 17
1985no dataSep 12no dataSep 23
1984Jun 23no dataJun 10no data
1983Jun 16Sep 12Jun 14Sep 20
1982Jun 20Sep 13Jun 9Sep 14
1981Jun 18Sep 18Jun 16Oct 4
1980Jun 17Aug 4Jun 7Sep 1
1979Jun 21Sep 13Jun 1Sep 15
1978Jun 27Aug 15May 25Aug 19
1977May 28Sep 14May 28Sep 17
1976Jul 3Sep 1Jul 3Sep 28
1975Jun 26Aug 25Jun 26Sep 19
1974Jun 12Aug 10Jun 11Sep 3
1973Jun 21Sep 4Jun 20Sep 19
1972Jul 5Sep 13May 26Sep 21
1971Jun 11Sep 4Jun 1Sep 15
1970Jun 16Sep 4Jun 16Sep 15
1969Jun 30Sep 18Jun 2Sep 23
1968Jul 1Aug 15Jul 1Sep 5
1967Jun 24Sep 13May 21Sep 13
1966Jun 14Sep 4May 24Sep 16
1965Jun 27Aug 1May 30Sep 16
1964Jun 23Aug 21Jun 23Aug 28

"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.