Cooler Temps on the Way as Meteorological Fall Starts This Week

Cooler temperatures will arrive right on cue this week as the start of the meteorological fall is on Thursday.

A humid Monday is in the forecast, with temperatures reaching a high between 80 and 86 degrees for the Chicago area, but then a cold front will sweep across the region bringing cooler temps on Wednesday and Thursday.

There is a 30 percent chance of showers and thunderstorms during the day on Tuesday and through the night. High temps will reach into the mid 80s that day but then will only be in the upper 70s inland on Wednesday and in the lower 70s by the lake. On Thursday through Sunday, highs in the mid 70s and lower 80s are in the forecast.

The meteorological autumn begins on Thursday, Sept. 1 and continues through Nov. 30. The meteorological autumn is different than the astronomical autumn, which starts on Sept. 22. The astronomical seasons are based on the position of the Earth in relation to the sun while the the meteorological seasons are based on the annual temperature cycle, according to the National Centers for Environmental Information.

Here is a more detailed look at the forecast:

• Sunday night: Partly cloudy. A chance of showers and thunderstorms south through sunset. Areas of fog after midnight. Lows in the upper 60s. Northeast winds 5 to 10 mph becoming less than 5 mph. Chance of precipitation south 30 percent.
• Monday: Partly cloudy. Areas of fog in the morning. Highs in the mid 80s inland...but only around 80 near the lake. East winds 5 to 10 mph.
• Monday Night: Mostly clear in the evening then becoming partly cloudy. Lows in the upper 60s. East winds 5 to 10 mph in the evening becoming southeast after midnight.
• Tuesday: Partly sunny with a 30 percent chance of showers and thunderstorms. Highs in the mid 80s. Southwest winds around 5 mph.
• Tuesday Night: Partly cloudy with a 30 percent chance of showers and thunderstorms. Lows in the upper 60s in the suburbs... But in the lower 70s downtown. West winds around 5 mph in the evening becoming northwest after midnight.
• Wednesday: Partly sunny with a 20 percent chance of showers and thunderstorms in the morning...then mostly sunny in the afternoon. Highs in the upper 70s inland...but only in the lower 70s near the lake.
• Wednesday Night: Mostly clear. Lows in the lower 60s.
• Thursday Through Sunday: Mostly clear. Highs in the mid 70s to lower 80s. Lows in the lower 60s.

more info

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