Chicago wouldn't be Chicago without the Lake Michigan weather. Chicago's location on the lake's southwest shore allowed the town to develop immediately after its integration in the 1830s into the core of producing, transport and railroading.
Lake Michigan also has helped Chicago weather to be identified worldwide as blustery, freezing and home to some breathtaking winter storms, with the latest blizzard in February making the record books as the third-largest in the Windy City's history.
The following is a brief briefing on how and why Lake Michigan and the other Great Lakes have such a significant influence on Chicago weather.
The five Great Lakes (Michigan, Huron, Superior, Erie, and Ontario) primarily act as a vast heat sink, moderating the temperatures of their shores. The lakes also become large humidifiers, escalating the amount of moisture that floats in the air all year round.
Which means that in the winter, this considerable moisture condenses and becomes snow when it hits shore, leading to what are known as "snow belts" on the downwind lake shores.
Areas on the downwind sides of the lakes such as Cleveland, Ohio; Erie, Pennsylvania; and Buffalo, New York (Lake Erie); Syracuse, New York (Lake Ontario); etc. often receive what is known as "lake effect" snow, receiving way more snow than other locations on the same latitude. For example, some parts along the shore of Lake Superior have recorded snowfall of up to 350 inches in just one year!
Yet Chicago weather isn't really impacted by lake effect snow resulting from the fact that the prevailing westerly winds that cross the region take on moisture from Lake Michigan after going through (some would say through) Chicago.
That's not to say that the Lake Michigan condition doesn't occasionally drop a significant amount of snow in Chicago. The uncommon northeasterly winds at times do bring on the type of blizzards that are so well known in snow belt locations.