Question

What does it mean when it thunders in December?

Answer 1

When it thunders in December the thunder in December usually but not always means that a cold front is moving in soon and that a big snowstorm or other major winter storm event is on it's way soon.

So if you hear thunder during December or at anytime during winter expect a major winter storm to come a few weeks later.

Answer 2

Thunder In December means that a cold front is on it's way and that you can expect very cold weather or even a major snow storm event.