Everyone is cracking down on skate spots nowadays, so it's slim pickings for skaters all over. What you need to do is find some new spots. Trust me, they are out there. Skate your box and ramps as much as you can, and search your town for new terrain. Check out warehouse districts, or industrial areas.
Chances are they have some stuff to skate, and they are usually deserted on the weekends.
Once you're rolling, you won't even notice the cold. You could also try to get a local park to be open on the weekends. You need to ollie slightly over the rail, and smack the tail into the blunt position. Try ollieing over the rail into a tailslide to get the feel of it. It feels different because you are balancing on a rail, which is skinnier than a ledge.