Halloween Forecast For Illinois: Coldest Air Of The Season Expected

ILLINOIS — You may want to buy a warm Halloween costume this year, or make sure to put on some extra layers, as the "coldest air of the season" arrives right before Halloween, according to the National Weather Service.

While Thursday and Friday will have highs in the 70s, the weather will turn wet and cool for the weekend. The weather service said "sharply colder" temps will move in behind a cold front on Friday, and will bring the first hard freeze of the season just in time for trick-or-treating.

Temperatures next week, from Monday onward, will have highs in the 30s and 40s, and lows in the 20s, according to the weather service.

AccuWeather forecasters said a "bone-chilling cold" will grip the Midwest and Great Lakes around Halloween. Temperatures will 10 to 20 degrees below the historical averages for late October, according to AccuWeather.

"The fall chill is expected to settle in across the entirety of the Midwest by early next week. Temperatures are also expected to fall well below historical averages across the Plains. Children in places like Chicago, Minneapolis and even Oklahoma City may want to consider wearing extra layers underneath their costumes to stay warm," AccuWeather Meteorologist Brandon Buckingham said.

Here is the latest local forecast from AccuWeather:

Thursday: Rather cloudy and mild with a couple of showers

Friday: Mostly cloudy, breezy and warm with a couple of showers and a thunderstorm; a dramatic cooldown over the next couple of days

Saturday: Mostly cloudy and cooler; coldest air of the season thus far arriving over the next few days

Sunday: Cooler with periods of rain

Monday: Sunshine, but cold

Tuesday: Breezy in the morning; otherwise, some sunshine giving way to clouds and chilly with a shower in places in the afternoon