Last Frost Day

Frost history / Douglas Converse Co Ap, WY

Douglas Converse Co Ap, WY: frost dates by year

Last spring and first fall frost at NOAA station USW00094057, 1999 to 2024, measured from daily minimum temperatures.

Elevation 4,929 ft, 42.797, -105.386. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianMay 24Sep 18
EarliestMay 4 (2018)Aug 23 (2015)
LatestJun 13 (2008)Oct 9 (2007)
Trend4.0 days earlier per decade2.5 days later per decade
Years with data2426

At 28°F (hard freeze) the median last spring date is May 9 and the median first fall date is Oct 5.

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 15Apr 30May 15May 30Jun 14Jun 292000201020202000: May 192001: Jun 52002: May 252003: May 202004: Jun 12005: May 282006: May 142007: Jun 82008: Jun 132009: Jun 82010: May 302011: May 192012: May 142013: May 52014: Jun 92015: May 202017: May 202018: May 42019: Jun 102020: May 262021: May 132022: Jun 12023: May 72024: May 22

First fall frost (32°F)

Aug 13Aug 28Sep 12Sep 27Oct 12Oct 272000201020201999: Sep 132000: Sep 72001: Sep 92002: Sep 212003: Sep 142004: Oct 22005: Sep 142006: Sep 192007: Oct 92008: Sep 142009: Sep 282010: Sep 32011: Sep 212012: Oct 32013: Sep 272014: Sep 112015: Aug 232016: Sep 102017: Sep 172018: Sep 222019: Sep 222020: Sep 72021: Sep 172022: Oct 52023: Sep 252024: Oct 1

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
2024May 22Oct 1May 4Oct 23
2023May 7Sep 25Apr 24Oct 7
2022Jun 1Oct 5May 22Oct 8
2021May 13Sep 17May 9Oct 13
2020May 26Sep 7May 8Sep 10
2019Jun 10Sep 22May 4Oct 2
2018May 4Sep 22Apr 27Oct 5
2017May 20Sep 17Apr 30Oct 9
2016no dataSep 10no dataSep 10
2015May 20Aug 23May 11Oct 24
2014Jun 9Sep 11May 13Oct 3
2013May 5Sep 27May 3Oct 5
2012May 14Oct 3May 12Oct 4
2011May 19Sep 21May 13Sep 21
2010May 30Sep 3May 8Oct 20
2009Jun 8Sep 28May 9Sep 28
2008Jun 13Sep 14May 11Oct 7
2007Jun 8Oct 9Apr 20Oct 15
2006May 14Sep 19May 11Sep 28
2005May 28Sep 14May 12Oct 5
2004Jun 1Oct 2May 14Oct 30
2003May 20Sep 14May 20Oct 1
2002May 25Sep 21May 9Sep 22
2001Jun 5Sep 9May 7Oct 6
2000May 19Sep 7May 13Sep 22
1999no dataSep 13no dataSep 13

"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.