I don't run in weather lower than 30 degrees in CHICAGO. It's not worth it. Save the run for a better day.
However, even though running on a treadmill is a surface that I run on weekly, I only run on it twice a week.
And I never do it on back to back days. I think the treadmill can be a very effective running tool if used correctly,
but if not used correctly, it can lead to injuries. So i'm forced into low mileage when I have to endure cold weather
spells.
There are a couple of indoor tracks( but limited to one day out of the week) that are available to me, so I will be able to get some speed sessions/vo2max stuff in. But other than that, I will not be able to do a long run until it gets warm.
I'm looking at about 25-30 miles per week for the next three weeks or so, which is decent. Plus I'll do a lot of running drills and strength training.
10 miles on the treadmill - Tuesday
Hit a university indoor track for 5 miles worth of speed/interval work
10 miles on the treadmill - Thursday
I will probably jump out in zero weather for a quick slow 15 min run, too, or whatever I can muster.
The good thing about this is that body will get a lot of rest and recovery, and will be eager and ready to do some serious training come February.