Dear Tom,
Where were Chicago temperatures taken in the 1800s?
Ricky E. Stone, Chicago
Dear Ricky,
Sporadic Chicago temperature records taken at Fort Dearborn, on the banks of the Chicago River near Lake Michigan and a few other locations, date back to 1830. Temperature records have been continuous here since October 1870 with the exception of a two-week period after the October 1871 Great Chicago Fire. During the late 1800s, the city’s official thermometer was moved frequently, but was always located downtown close to Lake Michigan. Through late 1970, readings were taken with liquid-in-glass thermometers in latticed shelters that allowed free air movement but still shielded the thermometer from sunshine and precipitation. Today the National Weather Service uses electronic sensors, but many local cooperative observers still use liquid-in-glass instruments.
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Tom Skilling is chief meteorologist at WGN-TV. His forecasts can be seen Monday through Friday on WGN-TV News at noon and 9 p.m.
Write to: ASK TOM WHY, 2501 Bradley Pl., Chicago, IL 60618 or asktomwhy@wgntv.com (Mail volume precludes personal response.)
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