If you like riding long, now is a good time to explore new roads, new routes, and find new favorites.
Some think summer is the time to explore. I see the logic, but now, as the weather is getting colder, riding hard is trickier, and the cold air reduces the likelihood of taking the KoM on a Strava segement. So, December is a great time to bundle up, fill your pockets with food, plug a new route into your head unit, and wander some place different. Explore and experiment now, so you have new roads mastered by the time it starts warming up again, and you can once again focus on speed.