Last Frost Day

Frost history / Sterling, CO

Sterling, CO: frost dates by year

Last spring and first fall frost at NOAA station USC00057950, 1951 to 2009, measured from daily minimum temperatures.

Elevation 3,974 ft, 40.628, -103.208. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 4Oct 1
EarliestApr 16 (2007)Sep 1 (1956)
LatestJun 7 (1998)Oct 28 (1963)
Trend1.5 days earlier per decade3.3 days later per decade
Years with data4846

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 14196019701980199020001951: Jun 21952: May 111953: May 141954: Jun 31955: May 31956: Apr 301957: May 171958: Apr 301959: Apr 251960: May 11961: May 151962: May 11963: May 221964: May 41965: May 101966: May 131967: May 141968: May 171969: Apr 291970: May 21971: May 121972: May 31973: May 31974: Apr 231975: May 71976: May 171977: Apr 211978: May 91979: May 111980: Apr 271981: May 201987: Apr 221988: May 41989: May 61990: May 101991: May 51992: Apr 261993: May 21994: Apr 301995: May 41996: Apr 291997: May 121998: Jun 72002: May 252006: Apr 272007: Apr 162008: May 122009: Apr 28

First fall frost (32°F)

Aug 13Aug 28Sep 12Sep 27Oct 12Oct 27Nov 11196019701980199020001951: Sep 161952: Sep 241953: Oct 41954: Oct 11955: Oct 71956: Sep 11957: Sep 221958: Sep 271959: Sep 291960: Oct 31961: Sep 151962: Sep 91963: Oct 281964: Sep 241965: Sep 171966: Oct 11967: Sep 271968: Oct 61969: Oct 51970: Sep 261971: Sep 191972: Sep 261973: Oct 111974: Sep 131975: Sep 201976: Sep 281977: Oct 21978: Sep 201979: Oct 31980: Oct 91981: Oct 11987: Oct 61988: Oct 211989: Oct 61990: Oct 81991: Oct 61992: Oct 81993: Sep 141994: Oct 241997: Oct 92001: Oct 52004: Oct 262006: Sep 282007: Oct 162008: Oct 142009: Oct 3

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
2009Apr 28Oct 3Apr 8Oct 3
2008May 12Oct 14May 11Oct 14
2007Apr 16Oct 16Apr 14Nov 1
2006Apr 27Sep 28Apr 27Oct 18
2004no dataOct 26no dataOct 31
2002May 25no dataMay 9no data
2001no dataOct 5no dataOct 16
1998Jun 7no dataApr 29no data
1997May 12Oct 9May 12Oct 9
1996Apr 29no dataApr 29no data
1995May 4no dataApr 27no data
1994Apr 30Oct 24Apr 28Oct 24
1993May 2Sep 14Apr 21Oct 9
1992Apr 26Oct 8Apr 25Oct 8
1991May 5Oct 6May 1Oct 6
1990May 10Oct 8Apr 7Oct 9
1989May 6Oct 6May 1Oct 19
1988May 4Oct 21May 3Oct 23
1987Apr 22Oct 6Apr 11Oct 11
1981May 20Oct 1Apr 14Oct 22
1980Apr 27Oct 9Apr 24Oct 9
1979May 11Oct 3May 10Oct 3
1978May 9Sep 20Apr 20Oct 3
1977Apr 21Oct 2Apr 4Oct 9
1976May 17Sep 28Apr 7Oct 18
1975May 7Sep 20Apr 19Sep 21
1974Apr 23Sep 13Apr 22Oct 15
1973May 3Oct 11Apr 16Oct 27
1972May 3Sep 26Apr 4Oct 24
1971May 12Sep 19Apr 9Sep 19
1970May 2Sep 26May 1Oct 8
1969Apr 29Oct 5Apr 28Oct 12
1968May 17Oct 6Apr 28Oct 18
1967May 14Sep 27May 2Oct 16
1966May 13Oct 1May 13Oct 1
1965May 10Sep 17May 10Nov 8
1964May 4Sep 24Apr 13Sep 27
1963May 22Oct 28Apr 30Oct 28
1962May 1Sep 9Apr 13Sep 9
1961May 15Sep 15Apr 28Oct 19
1960May 1Oct 3Apr 17Oct 23
1959Apr 25Sep 29Apr 22Oct 3
1958Apr 30Sep 27Apr 30Oct 1
1957May 17Sep 22Apr 26Sep 22
1956Apr 30Sep 1Apr 29Oct 14
1955May 3Oct 7Apr 13Oct 7
1954Jun 3Oct 1May 3Oct 14
1953May 14Oct 4May 12Oct 4
1952May 11Sep 24Apr 14Oct 6
1951Jun 2Sep 16Apr 22Oct 18

"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.