CHICAGO — Take a deep breath, open the windows, and enjoy it while it lasts: Chicago’s brief break from scorching summer heat will end this weekend, with humid, 90-degree weather returning next week, meteorologists warn.
Thursday marked the first time in 33 days that the city’s high temperature didn’t reach at least 80°F, a moment of relief in what’s shaping up to be Chicago’s fifth-hottest summer in 154 years, according to WGN’s Bill Snyder.
Back to the Sauna by Saturday
The reprieve will be short-lived, with Thursday’s high around 74°F and Friday’s forecast at 80°F with low humidity. But by Saturday, the oppressive heat will return, bringing with it the muggiest conditions of the season.
“Then it’s back in the soup,” Snyder said. “Back in the sauna next week.”
The forecast reflects an ongoing trend: 29 of the past 31 days have featured above-average highs, and Chicago has already seen 18 days of 90°F+ temperatures this summer — one more than the typical full-season average of 17.
Humidity to Surge, Thanks to Corn and the Tropics
Two main forces are driving this year’s excessive humidity:
- The Bermuda-Azores High, a pressure system usually located in the middle of the Atlantic, has drifted west, pumping tropical air directly into the Midwest.
- And yes, it’s true: Illinois cornfields are adding to the discomfort.
Known as “corn sweat” — or evapotranspiration — the mature corn across Illinois emits a staggering 35 billion gallons of water daily into the air, according to the National Weather Service in Central Illinois. That’s enough moisture to fill over 52,000 Olympic-sized swimming pools, making the air stickier and heat more oppressive.
Historical Heat Streaks Shattered
Chicago had logged 32 consecutive days of 80-degree highs before Thursday — the sixth-longest streak in city history. The city’s average temperature so far this summer is 75.8°F, about 3.5°F above normal.
By comparison, the record-setting summer of 2012 had already seen 30 days over 90°F at this point in the season.
What to Expect Next Week
- Highs in the upper 80s and low 90s
- Peak humidity levels starting Saturday
- A continued “heat dome” pattern, with periodic storm chances cycling along the outer edge
- No major cooldown in sight
“Give the AC a quick break now,” Snyder said. “God knows it’s been working overtime.”
How are you preparing for the heat to return? Share your cool-down strategies with us at ChicagoSuburbanFamily.com.
