The Recorded Climatic History of Fort Collins, Colorado

by:

Nolan J. Doesken, Assistant State Climatologist, Colorado Climate Center, Dept. of
Atmospheric Science, Colorado State University, Fort Collins, CO 80523.  (March 23, 2000)
Nolan@ccc.atmos.colostate.edu         (970) 491-8545    

Continuous and consistent daily weather records for Fort Collins date back to 1889, with some incomplete records going back into the 1870s. Unlike many other early Forts, there were no written weather records from Fort Collins.

Climatic Traits of Fort Collins

Many years of observation have revealed the following climatic traits for Fort Collins:

Generous sunshine, little precipitation except in spring, comfortable daytime temperatures much of the year, good visibilities, low daytime humidity (sometimes uncomfortably low), large day-night temperature variations, abrupt weather changes, plenty of mild winter days, but occasional extreme cold, little snow in mid winter, more in spring and fall, snows rarely linger -- chinook "snow-eater winds" help remove winter snows, snow in shade melts reluctantly regardless of temperature, occasionally extremely early (September) and late (May and even June) snows, light winds much of the time, but occasional major windstorms especially winter and spring, smog layers visible on calm days in fall and winter, localized thunderstorms and often intense afternoon and evening thunderstorms rare late at night or in morning, thunder common from late April into mid September, summer rains usually feel cold, hail very common, threats of tornadoes rarely materialize.

Notable climatic events observed through history in Fort Collins
June 9-10, 1864	Major flood on Poudre River and elsewhere across eastern Colorado
1893	Driest year in Fort Collins recorded history: 7.13"
February 1899	Coldest February on record, 6 nights below -- 30 F
Christmas 1899	No winter coats needed -- same condition Christmas 1999
April 1900	10+ inches of moisture, wettest month in Fort Collins history city-wide
September 20-21, 1902	6+ inches of rain, campus flooded
May 20-2 1, 1904	Huge floods on Poudre River from extreme rains near Livermore
Dec 1-5, 1913	Fort Collins greatest snowstorm
Summer 1915	Coolest summer in recorded history
1921	Huge April snowstorm in foothills, high water in early June
Jun 1923	Heavy rains, rapid snowmelt, Poudre River flooding
January 1930	Coldest month in Fort Collins recorded history -- t(mean) +9.5 F
1930's	Dustbowl drought out on plains, not as bad here -- but quite dry with extreme variability in temperatures
1934	Hottest, driest year of the dustbowl
September 1938	Flash flood in foothills west of town. Campus flooded
1940's	Cool, damp decade
November 1946	Heavy snows early in month. Eastern plains snowbound
January 1949	Great Plains blizzard -- Fort Collins spared the worst of it
Feb. 1, 1951	-41 F, coldest temperature in Fort Collins history -- trees killed
1954	Severe drought -- hottest year in Fort Collins history, most temperatures of 100+ in recorded history
1957	Wet spring ended 5-year drought
1961	Wettest year in Fort Collins history 28.43 (21" fell May -- Sep)
June 13-19, 1965	Severe flooding in much of eastern Colorado. Fort Collins spared
1966	Most recent severe drought year 7.34" precipitation
September 17, 1971	Early 15" snow destroys city trees
July 31, 1976	Big Thompson Flood affects many lives in Fort Collins
1972-1977	Last major drought for northern Colorado -- Horsetooth reservoir nearly empty Many severe downslope windstorms as well.
February 1978	Two week fog storm hides the city
May 5-6, 1978	Record May storm drops 27" of wet slop
July 30, 1979	3 ½" diameter hail stones, one fatality, other broken bones, worst hail storm in Fort Collins history
Winter l979-1980	Big snows from late October through April 114" total Roads fell apart, weeks of ice-packed roads.
June 1983	Snowmelt flooding on the Poudre. Taft Hill Road closed for 2 (?) weeks.
April 20, 1987	Easter Sunday cold front triggers home smoke alarms (rapid weather change Sunny, hot, cold front, thunder, snow.
October, 1991	Halloween arctic blast followed very mild fall -- thousands of mature trees killed.
March 6, 1990	Huge, wet snowstorm -- Roof bowed at Rocky Mountain High School resulted in evacuation 17" of wet snow -- nearly 4" of water content.
March 8-9, 1992	19" snow -- last time Poudre schools had a snow day (I think).
Spring 1995	Cloudiest, wettest spring in history
Sept. 20-2 1, 1995	Wet snow drops thousands of tree branches
July 28, 1997	Fort Collins flash flood. 14.5" over quail hollow in 30 hours. Greatest rainfall in recorded history over urban area of Colorado
Oct. 24-25, 1997	Blizzard claimed 8 (?) lives in Colorado. 16" here, but quick recovery
Winter 1997- 98	Very mild winter
Winter 1999-2000	Extraordinarily mild winter. Not even close to zero F.
April 1999	Extremely wet period -- Poudre River flooding April 30

Summary -- recent years have seen above average temperatures in Fort Collins with precipitation also above the long-term average (an unusual combination, based on past data. However, the basic features of our local climate remain very similar to what was observed in the 19^th Century.

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