Chicago’s 90s only 43% of last year’s—but more on the way

A new round of summer heat looms. The first in what may end up a string of six consecutive 90s appears poised to arrive Thursday afternoon. Building moisture levels in the days ahead promise to make the impending hot spell a muggy one. Just how high temperatures ultimately go will depend, as always, on wind direction, the extent of thunderstorm formation (or the lack of it) and just how much sunshine occurs.
Some clusters of thunderstorms combined with Wednesday’s widespread cloudiness restrain warming. Highs hold short of Tuesday’s 90° peak at O’Hare and 91° at Midway. It marked the 10th time this year the mercury has reached or exceeded 90° at the South Side site—only 43% last year’s 23 Midway 90s to date.
Past years with similar 90° counts to date have gone on to produce an average of nine additional 90° readings.
-Tom Skilling