Last Frost Day

Frost history / Longmont 2 Ese, CO

Longmont 2 Ese, CO: frost dates by year

Last spring and first fall frost at NOAA station USC00055116, 1951 to 2025, measured from daily minimum temperatures.

Elevation 4,950 ft, 40.169, -105.078. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 3Oct 1
EarliestApr 18 (1980)Sep 9 (2001)
LatestJun 2 (1951)Oct 31 (2024)
Trend1.1 days earlier per decade1.0 days later per decade
Years with data6160

At 28°F (hard freeze) the median last spring date is Apr 26 and the median first fall date is Oct 11.

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 31Apr 15Apr 30May 15May 30Jun 1419601970198019902000201020201951: Jun 21952: Apr 231953: May 141954: May 41955: May 171956: Apr 241957: May 181958: May 11959: Apr 221960: May 21961: May 21962: May 11963: Apr 231964: May 301965: May 91966: May 131967: May 141968: May 171969: Apr 281970: May 151971: Apr 281972: May 31973: May 31974: Apr 221975: May 31976: Apr 281977: Apr 211978: May 101979: May 121980: Apr 181981: May 101982: May 71983: May 181984: May 11985: Apr 271986: Apr 191987: Apr 221988: May 41989: May 61990: May 181991: May 31992: Apr 261993: May 101994: May 31995: May 41996: Apr 301997: May 121999: May 182000: May 132001: May 222002: May 242003: May 112004: May 12018: Apr 262019: May 212020: Apr 192021: Apr 232022: Apr 262023: Apr 232024: Apr 212025: Apr 20

First fall frost (32°F)

Aug 28Sep 12Sep 27Oct 12Oct 27Nov 1119601970198019902000201020201951: Sep 161952: Oct 51953: Oct 41954: Oct 141955: Oct 71956: Oct 101957: Sep 221958: Oct 11959: Sep 291960: Oct 161961: Sep 251962: Sep 101963: Oct 221964: Sep 271965: Sep 171966: Oct 11967: Oct 161968: Oct 41969: Oct 41970: Sep 261971: Sep 171972: Sep 301973: Sep 271974: Sep 281975: Sep 201976: Oct 71977: Oct 21978: Sep 211979: Oct 41980: Oct 171981: Oct 171982: Sep 141983: Sep 201984: Sep 251985: Sep 231986: Oct 111987: Oct 101988: Sep 191989: Sep 121990: Oct 71991: Sep 231993: Sep 131994: Sep 221995: Sep 211996: Sep 261997: Oct 91998: Oct 61999: Sep 212000: Sep 232001: Sep 92002: Oct 22003: Oct 122018: Oct 102019: Oct 52020: Sep 92021: Oct 142022: Oct 242023: Oct 142024: 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 20Oct 19Apr 7Oct 28
2024Apr 21Oct 31Mar 28Nov 5
2023Apr 23Oct 14Apr 23Oct 27
2022Apr 26Oct 24Apr 18Oct 28
2021Apr 23Oct 14Apr 22Nov 9
2020Apr 19Sep 9Apr 18Oct 16
2019May 21Oct 5Apr 13Oct 10
2018Apr 26Oct 10Apr 8Oct 14
2004May 1no dataApr 12no data
2003May 11Oct 12May 10Oct 26
2002May 24Oct 2May 24Oct 7
2001May 22Sep 9May 21Oct 6
2000May 13Sep 23Apr 21Sep 24
1999May 18Sep 21May 12Sep 28
1998no dataOct 6no dataOct 6
1997May 12Oct 9May 3Oct 9
1996Apr 30Sep 26Apr 30Sep 26
1995May 4Sep 21Apr 27Sep 22
1994May 3Sep 22Apr 30Oct 25
1993May 10Sep 13May 2Sep 14
1992Apr 26no dataApr 26no data
1991May 3Sep 23Apr 14Oct 5
1990May 18Oct 7May 1Oct 8
1989May 6Sep 12May 2Oct 16
1988May 4Sep 19May 3Sep 30
1987Apr 22Oct 10Apr 21Oct 10
1986Apr 19Oct 11Apr 19Oct 13
1985Apr 27Sep 23Apr 8Sep 26
1984May 1Sep 25Apr 28Sep 25
1983May 18Sep 20May 12Sep 21
1982May 7Sep 14May 6Oct 11
1981May 10Oct 17Apr 5Oct 18
1980Apr 18Oct 17Apr 17Oct 24
1979May 12Oct 4Apr 13Oct 22
1978May 10Sep 21May 9Oct 26
1977Apr 21Oct 2Apr 4Oct 11
1976Apr 28Oct 7Apr 18Oct 16
1975May 3Sep 20Apr 19Oct 17
1974Apr 22Sep 28Apr 16Oct 31
1973May 3Sep 27Apr 16Oct 11
1972May 3Sep 30May 2Oct 26
1971Apr 28Sep 17Apr 7Sep 19
1970May 15Sep 26May 2Oct 8
1969Apr 28Oct 4Apr 28Oct 5
1968May 17Oct 4Apr 24Oct 9
1967May 14Oct 16May 3Oct 16
1966May 13Oct 1Apr 28Oct 1
1965May 9Sep 17May 8Sep 24
1964May 30Sep 27Apr 19Sep 27
1963Apr 23Oct 22Apr 23Nov 1
1962May 1Sep 10May 1Oct 25
1961May 2Sep 25Apr 27Sep 30
1960May 2Oct 16Apr 30Oct 30
1959Apr 22Sep 29Apr 22Oct 3
1958May 1Oct 1Apr 30Oct 1
1957May 18Sep 22Apr 26Oct 25
1956Apr 24Oct 10Apr 20Oct 14
1955May 17Oct 7Apr 28Oct 7
1954May 4Oct 14May 3Oct 14
1953May 14Oct 4May 14Oct 4
1952Apr 23Oct 5Apr 10Oct 5
1951Jun 2Sep 16Apr 21Oct 21

"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.