While much of the U.S. prepares for a deep freeze, if the drop in temperature feels especially steep, that's because the country just experienced the warmest fall on record.
The average temperature across the country this autumn was 57.6 degrees, which is 4.1 degrees warmer than usual, according to the National Centers for Environmental Information, a division of the National Oceanic and Atmospheric Administration, USA Today reports.
It's also warmer than last year's fall, which averaged 56.8 degrees and was the warmest fall on record until it was surpassed this year, according to the NCEI. U.S. record keeping began in 1895, although accurate temperature information for the entire globe wasn't available until the early 1970s.
This year, eight states set records for their highest-ever fall temperatures, The Washington Post reports. And there's been even more record-breaking, with dozens of cities across the continental U.S. reporting their "first freeze" of the season weeks after the typical first freeze time.
The unusually warm temperatures are also at least partially the culprits behind a series of wildfires that have spread across the southern continental U.S. By the end of November, one third of the country was considered drought-stricken, CNBC reported.
Overall, 2016 may not surpass 2015 as the hottest year on record, thanks in part to a nation-wide cool down prompted by an influx of arctic air.
Combined with an active jet stream, Winter Storm Caly is expected to paint the northern U.S. white from coast to coast, moving from the Pacific Northwest through the plains, the Midwest and finally the northeast, according to The Weather Channel.