Science & Nature
No Snow Could Be Keeping Chicago From Record-Setting Cold
(EyeEm Mobile GmbH / iStock)
Temperatures on Tuesday will struggle to make it above zero, with wind chill readings plummeting to minus 20 to minus 30 degrees.
While Chicagoans know to expect frigid weather in January and February, it’s quite rare for the city to record these kinds of sub-zero temperatures when there’s no snow cover on the ground, according to the National Weather Service.
After digging into the archives, weather service meteorologists found that since 1942, fewer than 5% of Chicago’s sub-zero days have occurred with no snow: of 594 sub-zero days, only 28 lacked snow cover.
Snow cover reflects the sun’s warmth and radiates heat out into space, meaning that temperatures are usually significantly colder with snow cover than they are without it.
If there were snow pack on the ground under current conditions, temperatures could be even lower than the minus 8 degrees notched at O’Hare Airport at 9 a.m. Tuesday.
It was 40 years ago on Jan. 20 when Chicago recorded it coldest temperature ever: minus 27 degrees in 1985, with the lowest wind chill ever, at minus 57 degrees.
The extreme cold will stick around through Wednesday morning, with temperatures gradually inching back up into double digits.
People are advised to stay indoors if possible. When outdoors, cover up all exposed skin; frostbite can occur within 20 to 30 minutes, the weather service said.
One silver lining to the recent arctic blast: Ice cover on the Great Lakes is approaching near-normal levels, with only Lake Superior lagging, according to the Great Lakes Ice Tracker.
Great Lakes ice update for January 20, 2025: Combined 19% | Lake Superior 9% | Lake Michigan 18% | Lake Huron 25% | Lake Erie 39% | Lake Ontario 10% | #GreatLakes pic.twitter.com/l8i6n1qvCV
— Great Lakes Ice Tracker (@glicetracker) January 20, 2025
Contact Patty Wetli: @pattywetli | (773) 509-5623 | [email protected]