How did Chicago’s weather records start?

Dear Tom,
How did Chicago’s weather records start?
Candice Miller, Chicago
Dear Candice,
Concerns about shipwrecks on the Great Lakes served as an impetus for this country’s first organized weather observation system, in 1870. Weather observations were taken in Chicago and at 500 other sites across the U.S. by 1860, an effort interrupted by the Civil War. It wasn’t until Feb. 2, 1870, that Congress authorized the Secretary of War to collect weather data and to telegraph advisories on the approach of storms to mariners. President Ulysses S. Grant signed the bill seven days later, authorizing the Division of Telegrams and Reports for the Benefit of Commerce. Organized weather reports come from 22 sites, including Chicago, that telegraphed reports to Washington, where Signal Service professionals issued early weather forecasts. Chicago’s weather records began on Nov. 1, 1870.

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