I, too, did my initial recovery during the last part of a (Chicago) winter. For the first few months post-op, I didn't exert myself - too many complications from surgery. The following winter (last year), was really a non-winter. I had absolutely no issues, being a full year out from avr, and 6 months after rehab. This winter, after a few adjustments to my beta blocker dosage, I think I'll be feeling better and able to do more than I could for several years before surgery. Take it slow, let your body tell you how much to push. You'll be fine.