After digging, I finally found last subzero wind chill readings for both Tupelo and Aberdeen. Sadly, nothing I've come across has wind chill data going back to 1960. Might have to email someone higher up to get that. This also happened with no snow on the ground.
Tupelo, MS: -6 wind chill with actual temp of 7 at 7am January 17th, 2018
Aberdeen, MS: -6 wind chill with actual temp of 5 at 7am January 17th, 2018
Wind chill of 7 at Mobile with actual temp at 19 while Gulfport had wind chill of 3 with actual temp at 18. Both at 7am January 17th, 2018.
This was the day too that a patch of frost formed on the inside of my front door.