We had 10 inches of snow in late April, then went straight to early summer temps.. the Year Without a Spring. The Midwest tornado machine never had time spin up.
At least in our area (mid-south) there was also “no fall”, this year. One of the local TV mets described it as “Hot, hot, hot, COLD!” Then it stayed well below normal for about 2 months, with only a very few average or slightly warmer than average days. We certainly never got an “Indian Summer”. Once well into December, temps have been more typical (no unusually warm days, though), and typical December weather around here only rarely causes tornados, especially strong ones.