ROKA's Ultralight Pack Jacket is an amazing piece of attire for cold weather running. Despite weighing less than an energy bar and being able to pack down small enough to fit in your back pocket, it's wind- and water-resistant enough to keep you warm and dry even in the roughest weather conditions. Our own Isaac Smith loves it:

I was out trail running last week in 15º[F] degree weather with just a single base layer under it and I was perfect.

The Ultralight Pack Jacket comes in both men's (in "acid lime" or black) and women's (in "torch" or black) versions. Both are on sale for $88 (down from $175) as of 02/17/2018.