I get it, its colder now and you are less likely to go for a run. It can be hard to keep motivated when its so cold out, and maybe the gym is too far all of a sudden as the chilly air takes a toll on you.
There are however a few things you can do to adjust a little better to a nice Winter run.

Dress warm: LAYERS
Keep warm, but pile on layers that can removed if/when you become warm from working out/running

Stretch:
Do some warm-up stretches indoors before to warm up your muscles

Gym alternatives:
A little at home workout perhaps? Youtube is full of workout videos!

Do not accept excuses:
seriously.

photo courtesy of: Huff Post