Last Frost Day

Frost history / John Martin Dam, CO

John Martin Dam, CO: frost dates by year

Last spring and first fall frost at NOAA station USC00054388, 1951 to 2025, measured from daily minimum temperatures.

Elevation 3,814 ft, 38.063, -102.930. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianApr 28Oct 13
EarliestApr 2 (2016)Sep 19 (1971)
LatestMay 22 (2019)Nov 1 (1963)
Trend0.9 days earlier per decade0.9 days later per decade
Years with data5555

At 28°F (hard freeze) the median last spring date is Apr 15 and the median first fall date is Oct 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)

Mar 16Mar 31Apr 15Apr 30May 15May 3019601970198019902000201020201951: Apr 221952: Apr 101953: May 131954: May 31955: Apr 281956: Apr 301957: Apr 141958: Apr 291959: Apr 221960: Apr 301961: Apr 271962: May 11963: May 11964: Apr 211965: May 111966: May 131967: May 21968: Apr 241969: Apr 281970: May 21971: May 121972: May 11974: Apr 161976: May 171977: Apr 221990: May 101991: May 11997: May 91998: Apr 221999: Apr 172000: May 192001: Apr 212002: Apr 282003: Apr 102004: Apr 142005: May 122006: Apr 262007: Apr 262008: May 122009: Apr 92010: May 132011: May 32012: Apr 42013: May 52014: Apr 152015: May 122016: Apr 22018: Apr 192019: May 222020: Apr 182021: Apr 222022: Apr 182023: Apr 212024: Apr 92025: Apr 21

First fall frost (32°F)

Sep 12Sep 27Oct 12Oct 27Nov 1119601970198019902000201020201951: Oct 181952: Oct 71953: Oct 61954: Oct 151955: Oct 71956: Oct 211957: Oct 241958: Oct 101959: Oct 11960: Oct 201961: Sep 251962: Oct 181963: Nov 11964: Oct 61965: Sep 211966: Oct 151967: Oct 161968: Oct 31969: Sep 241970: Sep 261971: Sep 191972: Oct 191974: Oct 151975: Sep 221976: Oct 81989: Sep 231990: Oct 91997: Oct 251998: Oct 181999: Oct 12000: Oct 62001: Oct 62002: Oct 152004: Oct 142005: Oct 72006: Oct 192007: Oct 172008: Oct 242009: Oct 22010: Oct 262011: Oct 132012: Oct 82013: Oct 62014: Oct 292015: Oct 162016: Oct 52017: Oct 102018: Oct 142019: Oct 102020: Oct 162021: Oct 132022: Oct 172023: Oct 72024: Oct 312025: Oct 19

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
2025Apr 21Oct 19Apr 20Oct 19
2024Apr 9Oct 31Apr 9Nov 1
2023Apr 21Oct 7Apr 21Oct 15
2022Apr 18Oct 17Apr 16Oct 25
2021Apr 22Oct 13Apr 21Nov 1
2020Apr 18Oct 16Apr 18Oct 19
2019May 22Oct 10May 22Oct 11
2018Apr 19Oct 14Apr 19Oct 15
2017no dataOct 10no dataOct 27
2016Apr 2Oct 5Apr 2Oct 7
2015May 12Oct 16Apr 10Nov 7
2014Apr 15Oct 29Apr 15Nov 1
2013May 5Oct 6May 4Nov 1
2012Apr 4Oct 8Mar 10Oct 18
2011May 3Oct 13Mar 31Oct 14
2010May 13Oct 26Apr 8Oct 27
2009Apr 9Oct 2Apr 8Oct 2
2008May 12Oct 24Apr 27Oct 24
2007Apr 26Oct 17Apr 15Oct 20
2006Apr 26Oct 19Apr 26Oct 19
2005May 12Oct 7May 12Oct 7
2004Apr 14Oct 14Apr 13Oct 30
2003Apr 10no dataApr 10no data
2002Apr 28Oct 15Apr 4Oct 15
2001Apr 21Oct 6Apr 18Oct 6
2000May 19Oct 6Apr 16Oct 10
1999Apr 17Oct 1Apr 17Oct 4
1998Apr 22Oct 18Apr 17Oct 18
1997May 9Oct 25Apr 15Oct 25
1991May 1no dataApr 13no data
1990May 10Oct 9Apr 12Oct 9
1989no dataSep 23no dataOct 19
1977Apr 22no dataApr 4no data
1976May 17Oct 8Apr 1Oct 8
1975no dataSep 22no dataOct 16
1974Apr 16Oct 15Apr 16Oct 31
1972May 1Oct 19Apr 1Oct 24
1971May 12Sep 19Apr 7Oct 20
1970May 2Sep 26May 1Oct 8
1969Apr 28Sep 24Mar 29Oct 12
1968Apr 24Oct 3Apr 24Oct 18
1967May 2Oct 16May 1Oct 25
1966May 13Oct 15May 13Oct 15
1965May 11Sep 21May 9Nov 4
1964Apr 21Oct 6Apr 14Oct 19
1963May 1Nov 1Apr 23Nov 1
1962May 1Oct 18Apr 2Oct 24
1961Apr 27Sep 25Apr 16Oct 19
1960Apr 30Oct 20Apr 3Oct 31
1959Apr 22Oct 1Apr 13Oct 27
1958Apr 29Oct 10Apr 24Oct 22
1957Apr 14Oct 24Apr 13Oct 26
1956Apr 30Oct 21Apr 10Oct 25
1955Apr 28Oct 7Apr 8Oct 25
1954May 3Oct 15May 2Oct 27
1953May 13Oct 6Apr 18Nov 8
1952Apr 10Oct 7Apr 10Oct 7
1951Apr 22Oct 18Apr 12Oct 22

"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.