The last time something like this happened was 1994. You’ll probably remember assuming you’ve been there at least 5-6 years that about 5-6 years ago we had two winters back to back that were unbelievably mild. I remember it raining all winter one of those two. I remember not wearing a jacket or maybe once or twice December thru January. Maybe one snowfall that year. That was odd. We know that. But, it was great! It’s nice to enjoy something like the folks Ill assume in the southern part of Tennessee may have yearly. The thing with those zone 7b areas is they have the same plants that we do on most occasions but they get spring frosts when their plants are much further along than ours. So really, it’s more difficult for them than it is for us a lot of years.
I looked into living in zone 7b and people told me, you’d be surprised at the difficulty. And, I was.
Last year here in Aledo it was -12 twice. The rest of the winter just as you say was nothing, a complete breeze. I’m used to that here. If I see -15 once it’s just that, once… add in a few -10’s and -8’s and -3’s and that’s my winter.