The midwestern city of Saint Louis, in Missouri, saw the mercury hit 86 degrees Fahrenheit (30 degrees Celsius) on Tuesday, the highest temperature ever recorded in that month, after the heat peaked at 80F on Monday.

An El Nino weather pattern is at play, in addition to climate change, according to experts.

But the summery highs aren't expected to last, with temperatures set to quickly plunge back into deep winter chills.

Although weather climbed into the 70s in Chicago on Tuesday, it was set to dive below freezing when factoring in the wind chill by Wednesday morning, according to the National Weather Service.

It characterized the swing as "absolutely brutal" in a post on social media, which also warned of possible wind gusts over 50 miles per hour as a cold front moves in Tuesday evening.

The NWS summarized Chicago's weather pattern as seeing summer, spring, fall and winter "crammed into the next 24 hours."

Similar temperature swings are expected across the middle of the country, possibly bringing brutal storm patterns including tornadoes and hail.

Minneapolis-St. Paul, in Minnesota, saw a record February temperature of 65F on Monday, followed by blizzard warnings for Tuesday.

Canada also notched record heat, with Montreal hitting a daily record on Tuesday at 59F, according to the country's environment ministry.

Last month marked the warmest January the world has ever seen, according to the United States' National Oceanic and Atmospheric Administration (NOAA) and the European Union's Copernicus agency.

And despite the impending chill setting in, "February 2024 remains the odds-on favorite to be the warmest February on record," wrote climate scientist Zeke Hausfather on X, formerly Twitter.

Climate analyses for February are set to be released by NOAA on March 8 for US temperatures and March 14 for global temperatures.