Winter sucks

Looking back at my levels of exercise over the past couple months...

September: 21/30 days. October: 22/31 November: 19/30. And now we're closer to the end of December than we are the start and I've only worked out 9/19 of the days. At this rate I'll only get 14-16/31 at the most without overdoing it.

SAD is real and it majorly sucks. Any tips for winter motivation? (Plus I've got 5 exams coming up so... I expect it to get even worse :( )