Winter Running has been a struggle for me for a long time, I used to wimp out the moment the temperatures dropped below 5 degrees. This year I am determined not to let winter get the best of me, I have been running 5-7km 2-3x a week august until 2 weeks ago when the temperatures went to -30.
It's actually really wonderful to be able to get out and enjoy the outdoors when it's cold and your body warms up rather quickly. Now -30 is still a little on the cold side for me, but -15? Totally doable and actually enjoyable! 
What you'll need: 
Runners with grip: I got this saucony trail shoes last January and when it's icy or heavy snow they're great, a lot better grip than my usual. 
Warm socks: Wick away material that's a bit thicker to keep those toesies warm
Lined leggings: Lulu lemon has a couple lined with fleece that are great when it's chilly, when its a deep chill you might need another layer though
Wick away tops: light weight material that keeps the sweat from staying on your skin is important, it's not good to let sweat stick to your body and freeze. Smart wool is a great option
Hats/face warmer/scarf/mittens: Its important to keep your head warm, cover your mouth to breath when it's really cold and keep those hands warm. Mountain equipment co-op has a great selection for all this gear

It's a bit of gear, but now you're ready to run in any temperature and all conditions, nothing can stop you. Now put some tunes on and get moving