We had a Blue Norther blow through on January 1 that dropped the temperature by 50^o in one day, from 70 to 21. Brrrrr! I had plants in the greenhouse so set up the heat plug - a device that if the temperature drops to 37^o or below it allows the power to run through it (so I have a heater plugged into it and in the "on" position.)

Before that it was very warm for most of December. Unseasonably so.