New Balance NB Heat Hybrid Jacket - Insulated (For Men)

Quite possibly the warmest running jacket I've ever come across. Make sure you get it in your correct size as there is no hem/waist cord to tighten it down. Too big and you'll lose some warmth. Same with the cuffs, they have some elastic but if you get the jacket too big they won't keep the cold out. Hood is the same way, too big and it's not going to do you any good.
Like I said, super warm and breathes very very well considering how insulated it is. Light rain beads up on the exterior but it is no way water proof and I wouldn't even classify it as water resistant. Which is fine cause it doesn't claim to be.
I'm 5'9" 145-150 and the small is perfect.
I've worn it in the teens and upper single digits and been totally comfortable with a long sleeve lighter shirt on under it. I've also worn it with just a t shirt in the early mornings when it's started out in the 20's and gotten up to approaching 40 at the end of my run and been fine.
Only thing is if you sweat alot, it doesn't allow for a lot of evaporation so it will be a bit heavier and pretty wet when your done. Guess with that much insulation it's hard to find anything that would do that though.