Chicago Weather

With ‘summer-like' temperatures in Chicago as fall approaches, when will the leaves change color?

The first day of fall in Chicago looks to be 81 degrees

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Fall this year in the Chicago area is expected to receive a rather warm welcome when it comes to the weather.

According to the NBC 5 Storm Team, beginning Wednesday through the rest of the work week, temperatures are expected to increase and remain above-average, with highs in the upper 70s to mid 80s.

By Saturday, Sept. 23 -- the autumnal equinox -- a high temperature of 81 degrees is expected, the NBC 5 Storm Team says.

But the warm weather isn't the only part of the forecast leading up to fall. Here's a look ahead to next few days.

Wednesday

NBC 5 Meteorologist Alicia Roma reported showers and thundershowers were developing early Wednesday and will continue to develop through the mid-morning hours to the west, including in McHenry, DeKalb and Kane Counties. In those counties, a flood advisory was in effect until 10:15 a.m.

Some lightning was detected as part of the widely scattered storms, Roman said. Severe weather was not expected, however, some areas saw between two and four inches of rain.

According to the National Weather Service, morning thundershowers are expected to remain north of I-80.

Later Wednesday morning, around 10 a.m., the rain is expected to clear, though some clouds could linger, Roman said. By afternoon, the day looks to be mostly to partly sunny, Roman added.

High temperatures Wednesday are expected to be "more summer-like," in the mid 70s to low 80s, Roman said.

MORE: What could Chicago's winter look like? Here are the latest projections  

According to the Roman, the average high for this time of year is 74 degrees.

Thursday, Friday

Overnight Wednesday and into Thursday looks to be mostly dry, the NBC 5 Storm Team said. However, another chance for showers could move in late Thursday afternoon and into Thursday evening, according to Roman.

According to the NWS, the chance of showers Thursday evening is between 20 and 30 percent, with the greatest chance of showers or potentially a storm across northern and central Illinois.

The chance for showers returns again late Friday, Roman said.

According to forecast models, Friday afternoon and evening will see a higher chance of rain and storms, mainly near I-55 and to the Northwest.

Temperatures both Thursday and Friday remain mild, with highs in the mid 70s to low 80s, Roman said.

Saturday: First Day of Fall

The first day of fall looks to be dry, sunny and bright, with a high temperature of around 81 degrees.

And though some leaves may have started to change color, they may be on the duller side this year, Roman said.

According to NBC 5 Storm Team meteorologist Pete Sack, the green-pigmented chlorophyll in leaves activated by sunlight and photosynthesis both slow down in fall, a process that brings out the leaves' natural colors like red, yellow, orange and brown.

MORE: When do we fall back? Illinois' daylight saving time will soon end

While those colors will still be prevalent this fall, "peak fall foliage" may be shortened due to year-long drought conditions, as drier leaves fall from trees faster than those with some moisture content.

According to Sack, even above-average rainfall at this point in the year would not restore the typical length of peak fall foliage.

When will the leaves in Illinois change color?

According to the Smoky Mountains 2023 Fall Foliage Prediction Map, some areas across northern and eastern Illinois began to change color this week. By the week of Sept. 25, those colors will be a bit more bold, the map showed.

As those colors brighten, leaves in central Illinois will begin to change, the map showed, around the week of Oct. 2.

According to the map, peak fall foliage across Illinois looks to be between the week of Oct. 9 and Oct. 23.

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