(The Center Square) – Even though the official start of fall has come and gone, most of Illinois is experiencing a warming trend, with temperatures in the mid-80s.
Meteorologist Ben Duebelbeiss of the National Weather Service says a string of days with temperatures in the 80s wrapping up September may seem out of the ordinary, but it is not as unusual as some people might think.
“It’s pretty common to have temperatures into the 80s well into October,” Duebelbeiss said.
The mean date for the last 80-degree maximum temperature is Oct. 11.
“We’ve had 80-degree days as late as Nov. 1,” Duebelbeiss said.
At the end of August, the weather got everybody’s attention when Illinois experienced a stretch of days from Aug. 20 through Aug. 25 with temperatures well into the 90s. Even so, August this year did not wind up out of the norm for average temperatures, Duebelbeiss said.
“We actually finished August pretty close to normal, owing to some cooler temperatures at the start of the month,” he said. “At the beginning of August, there were several days with highs only in the 70s.”
The beginning of September is when the weather normally begins to change in Illinois. The equinox was Sept. 23, but fall is usually underway before that.
“In the weather world, Sept. 1 is the start of meteorological fall,” Duebelbeiss said.
In an average year, the average high to start September in Central Illinois is about 80 degrees. By the end of the month, the average high drops to about 73 degrees. The average low temperature on Sept. 1 is 62 degrees. By the end of the month, the average low is about 51 degrees.
That means temperatures this September are running warmer than normal.
“Summer seems to be hanging on a little longer than usual this year,” Duebelbeiss said.
Expect highs in the 80s through the weekend. Temperatures into next week are expected to be in the mid to lower 80s.