This semester a University of Illinois Department of Atmospheric Science student, Lauren Graham, worked to make available scanned images of the weather records for Fort Armstrong that cover the period 1820 to 1836. Fort Armstrong was located at the present-day Rock Island Arsenal. The original records were maintained and scanned by staff at the Rock Island Arsenal Museum.
These are the oldest official weather records that I have been able to find for Illinois. The records contain daily temperature readings taken at 7 am, 2 pm, and 9 pm, as well as comments on the weather. My favorite is a note in the first month about a “violent hurricane” on July 21 1820 (see image below). I’m sure it was not really a hurricane but either a tornado or severe thunderstorm with high winds.
Here is the press release of the story.
Here is the Fort Armstrong page containing the images and preliminary analysis.
The plans are to introduce more analysis of these data over the summer.