Sam, I'm a southerner who likes it warm and not particularly tough about cold weather. A couple of days ago the morning commute was low 30's and I wore: running shorts, running shirt, long sleeve jersey, jogging pants. All that was a little warm, but not enough to sweat in. I seem to go through it every winter so far, overdressing at first and arriving sweaty.
Just wear layers of thin, light clothes and gradually try less until you hit your comfort zone.