not 100% sure how accurate this is, but I'd assume that if the warm weather brings them out early and then it frosts again later on, then the extremely cold weather will kill them off and we won't have to worry as much about them in the summer...I know a few years ago we saw a couple ticks realllly early, then it frosted and we didn't see annnyyyy during the summer, I asked my grandad about it and he said it could attributed to this....