List of United States tornadoes in December 2021

In December, tornadoes are most likely in the southern states due to their proximity to the unstable airmass and warm waters of the Gulf of Mexico, with only occasional incursions farther north.

[2] After a small outbreak along with some isolated tornadoes at the beginning of the month, December unexpectedly produced two large, record-breaking tornado outbreaks during the middle of the month.

One supercell tracked over 250 miles (400 km) throughout the states of Missouri, Tennessee, Arkansas, Kentucky, spawning a family of 11 tornadoes, including two violent EF4 tornadoes.

The outbreak was unprecedented since tornadoes in that region during late fall and early winter are rare, but tornadoes were confirmed as far north as southwestern Wisconsin.

It also set the record for the most active month for tornado activity in meteorological winter, surpassing the previous record of 216 set in January 1999.