What is the lowest percent of possible sunshine ever recorded in a Chicago January?

Posted: Feb 1, 2023 / 09:55 PM CST

Updated: Feb 2, 2023 / 09:32 AM CST

Dear Tom,

You’ve been keeping us updated on how cloudy this January has been. What is the lowest percent of possible sunshine ever recorded in a Chicago January?

Steve Zalutsky Chicago

Dear Steve,

January and December are historically Chicago’s cloudiest months, each averaging just 40 percent of possible sunshine. This January totally underachieved, logging a record-breaking 18 percent of possible sunshine buoyed by 18 totally cloudy days. We asked Chicago climatologist and weather historian Frank Wachowski, who is also the keeper of the city’s sunshine records, and he quickly responded that the city’s previous dreariest January occurred in 1998, logging just 20 percent of its possible sunshine. However, that dreary month still holds the record for the greatest number of totally sunless days in January, with 20.