Wednesday forecast: October begins with increasing clouds and warm temps in Chicagoland

If you’re eager for some crisp October air, well, you’ll just have to wait for later in the month.

Because the start of October this year will feel more like July.

The first day of October on Wednesday will actually be the coolest day of the next few, with high temperatures reaching the low 80s inland and the mid-70s near Lake Michigan. That’s still well above the average high of 69 for Oct. 1 in Chicago.

There will also be considerable cloudiness, another change from recent days.

Thursday is forecast to bring decreasing clouds and temps a little warmer than Wednesday.

Then, things really heat up into the coming weekend, with abundant sunshine and temps creeping close to 90 in some locations around Chicagoland (see more below).

The upcoming weekend will be sunny and hot, with high temps in the upper 80s forecast for inland locations. These areas will likely at least flirt with a 90-degree day in October on Friday into Saturday.

90 in October

How rare is it for Chicago to reach 90 degrees in October?

Well, it’s rare, but not totally unprecedented.

Frank Wachowski, a longtime weather observer and friend of Tom Skilling who’s been helpful to the WGN Weather Team over the years, sent an email of recorded 90-degree days in Chicago from 1871-2024.

As you can see, there have been six recorded 90-degree days in October in Chicago during that time, all within a 20-year span from 1951-71. The last time it happened was in 1971, when it reached just over 90 on each of the first two days of October.

While temps will soar to July-like highs on Friday into Saturday, we most likely will not quite reach that 90-degree mark this year. But if we do, it’ll add to the 90-degree ledger during what’s been a hot 2025 in Chicagoland.

Forecast mean maximum temperature anomaly: Oct. 2-6

Stunning daytime temperature anomalies appear this weekend into early next week, with highs averaging some 15-20 degrees above normal across a large portion of the Upper Midwest and Great Lakes. 

6-10-day temperature: Oct. 5-9

Above normal warmth is expected to continue for the eastern two-thirds of the U.S. through at least the opening nine days of October.  

Forecast total rainfall through Monday, Oct. 6

No rainfall is in the forecast for the first days of October, coming on the heels of the seventh-driest September on record for Chicago.

which means Chicago will finish with the seventh-driest September on record.

We received just four days of measurable rain and one day of a trace of rain last month, for a total of 0.49 inches. That’s 2.7 inches below the normal total of 3.19 inches at O’Hare International Airport for September.

No improvement for drought conditions is coming, as another full week with no rain is expected across the Chicago area and a large portion of the Midwest and Ohio Valley.

The next chance for rain in our area doesn’t arrive likely until next week Monday into Tuesday.