Well as it is soooo cold, snowy and icy here in Bucks. I decided to "cheat" and do my 27min run on the treadmill - done...but not as satisfying as running outside in the fresh air. Hubby is pounding it out down the shed as I type. We have decided to do Week 6/3 again once we can get outside without breaking a hip (!) as it just doesn't feel quite the same. I had the treadmill set on flat rather than incline so felt it was easier. But there again, better safe than sorry, and better than nout.
Be careful out there! One little slip and you're possibly out for weeks.