In 2012, former Illinois State Climatologist Jim Angel and Lauren Graham, a recent University of Illinois graduate, obtained original weather records from the 1820s and 1830s from the Rock Island Arsenal Museum. These are believed to be the oldest official weather records ever found in Illinois.
The records, hand written with ink and quill, captured temperature readings taken at 7 a.m., 2 p.m., and 9 p.m. each day at what was then called Fort Armstrong on Rock Island from 1820 to 1836. According to Angel, the temperature data showed remarkable accuracy given the technology of the day. Today we can record the high and low temperatures for each day as well as hourly temperature using electronic sensors. Back then they had to read glass thermometers on a porch on the north side of a building.
“Compared to modern-day normal temperatures, the data were very reasonable,” Angel said. “When they’re in the same ballpark with today’s averages, you feel better about accuracy of the numbers.”
Although Angel and Graham didn’t see any temperatures that would break today’s records, they did find some interesting historical insights. For example, on Feb. 8, 1831, the observer reported a temperature of -12 degrees at 7 a.m. and “30 inches of snow on the level,” which is likely a multi-day accumulation. Also, the records referred to a “violent hurricane” on July 21, 1820, in the first month of reports, which likely referred to either a tornado or severe thunderstorm with strong winds.
Other comments in the weather records referenced ducks flying south, the condition of crops, and other events of everyday life.
“It was like reading someone’s diary,” Graham said. “We wondered about the differences in how they perceived weather events and if those perceptions were the same as they are today.”
Historical data of this type can be used to extend the record further back than what is used today. Unfortunately, a gap still remains between 1836 and the next oldest weather records at Peoria, which has continuous reports going back to 1856.
“These records give us a sense of a bigger picture of the weather in Illinois in the 19th century,” Angel said. Images of the original records can be found on the State Climatologist's website.
