A fourth consecutive day of 90° temperatures—more 90s than occurred in all of 2004-—is predicted Tuesday. But, with soil moisture-levels low in response to this year’s extreme drought, there’s less moisture returning to the atmosphere through evaporation—and that holds humidities lower than they might otherwise be. It’s a development which spares area residents the full measure of discomfort that long periods of 90° temperatures can bring. This “heat” is also occurring with the sun on a late season trajectory across the sky each day. The lower sun angle reduces sunlight intensity and no doubt contributes to the comparative tolerability of the current round of heat. But, the number of remaining truly hot days this time of year is finite.
It’s been ten years (since 1995) since Midway Airport has recorded more 90s than the 35 which will be on the books here after today.
WGN-TV Chief Meteorologist Tom Skilling and the WGN Weather Center staff provide daily coverage of weather in the Chicago area.
