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As for a geographic reason, the city does experience winds because of its location. The prevailing winds come from the west and southwest. That area is flat with little resistence to the weather. When the wind is from the east or northeast, it travels over Lake Michigan with no resistence at all. During Winter the winds are extremely harsh. Chicagoans refer to it as "the hawk." There are dangerously windy areas downtown because of the deep valleys caused by the tall buildings but these didn't exist when the term was first used.
The most accepted place is from New York in the early 1890s. It was used as a description of the big mouthed Chicago politicians who were boasting the city as the "best possible" site for the upcoming World's Fair to commemorate the 400 yr anniversary of Columbus' first voyage (same scene as the lost attempt to host the 2016 Olympics).
"...these boosters were full of hot air, and tension between backers of various cities came to its zenith in the race to obtain the 1893 World's Columbian Exposition in celebration of the four-hundredth anniversary of Columbus's landing (one year late). Having arisen from a swamp in just more than 60 years, reversed the flow of the Chicago River, and made a stunning rebound from the Great Fire of 1871, city leaders in the early 1890s felt Chicago to be an obvious choice to demonstrate American enterprise and ingenuity to the rest of the world, not to mention establishing Chicago's status as a world-class city. They therefore organized a company to generate the necessary funds to underwrite the exposition. However, when Illinois Senator Shelby M. Cullom introduced a bill into the United States Congress in favor of federal support for the exposition, he neglected to specify that Chicago would play host. Immediately, a vicious contest arose to obtain the event, with Chicago, New York, Washington, D.C., and St. Louis (which would host a similar affair only 10 years later) emerging as the major players. Charles A. Dana, editor of the New York Sun, wrote an editorial in his paper snobbishly discounting the "nonsensical claims of that windy city. Its people could not build a world's fair even if they won it." According to most accounts, it is this editorial that popularized the "Windy City" nickname on a national basis."
The term "Windy City" was first published in the New York Sun. Because of the continental rail lines at the time, the New York Sun was distributed nation-wide through the mail.
I think the term posibly existed locally or in the region as a windy city. There is legend that the term was used in the 1850s as a promotion for a land speculation that the city was next to the lake and cool breezes swept over the land making a great place for a pre-electric resort.
The Great Chicago Fire in 1871 is another likely source of the use of the term. The City had been through a long drought and it was a hot Oct. Once the fire started it was out of control...mostly because of the prevailng SW winds. By the time it reached the blaze it changed to tornado like winds.
A possible contribution to the source is from the 1880s and 90s. Chicago was the location of many workers' rights groups. This was because of the many factories, meat processing plants, railroads and catalog houses. There was much controversy from all sides of the issues and it was watched by the nation in the newspapers.
A riot took place 5/1/1886 that was ignited by a bomb and shots being fired by workers and police. A controversial trial and quick executions followed. The anti-workers side of the issue was published in the Chicago Tribune which was a non-union shop and its publisher was one of the windiest editors and most powerful men in Chicago.
A walkout strike took place 5/11/1894 that would affect the nation. The actions and reactions were serious but could have been interpreted as a lot of wind was blown around by both parties before and continued after it happened. The walkout was backed by the ARU which refused to work on any trains with a Pulmann car. The Army was sent from Fort Sheridan to stop yhe violence. After another trial and a Supreme Court decision but an advance for unions years later. Again the same editor/publisher/owner, Joseph Medill, lambasted organized labor...more wind to enter the minds of NY newspapers.
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