DOWNTOWN — While the fall equinox doesn’t happen until late September, many are tempted to pack up their swimsuits as August comes to an end. But you don’t need to throw out that summer bucket list just yet.
September could be slightly warmer and drier than average this year, said Bob Larson, a meteorologist for AccuWeather. The heat will be noticeable especially during the first week of September, when Larson predicts the city will see high temperatures in the 80s or even close to 90 degrees.
Here’s how Larson currently predicts the month will play out: The first week of September will be “very warm” and hotter than average, the second week will be “decidedly cooler,” the third week will be warmer than usual and the fourth week will see temperatures fall again.
That means temperatures will probably be slightly warmer than average, but the difference won’t be extreme, Larson said.
Last year the early fall heat was more extreme: September was 5 degrees warmer than average for the month as a whole, Larson said. The city even hit 95 degrees on Sept. 23, 2017, and there was a heat wave where every day was 90 or warmer Sept. 20-26.
“Pretty unusual to have it that hot that late in September,” Larson said. “We don’t think this September’s as warm as last year.”
Chicago’s Septembers start out fairly warm with an average high of 80 degrees on Sept. 1, Larson said, but the average high temperature drops to 69 degrees by the end of the month.
“We lose a good 10, 12 degrees in temperature as we go through the month, on average,” Larson said, noting September is a “transitional month” that leads the city from summer into fall.
The city could also be drier than usual this September, Larson said: Chicago typically get 3.25 inches of rainfall in September, but slightly less is expected for this coming month. That’ll still be better than last year, though, when the city got just 1/3 of an inch of rain throughout the month.