I don't commute when there is snow on the roads (tried it once and it was a little scary even with studded tires) so this winter in Cleveland was a bad year. Still there wasn't more than a dozen days I missed. I find there is very little that stops me from riding. Once youv'e ridden in weather you realize its not so bad. That includes rain, cold, wind, light snow, sleet, heat, etc. Its only the slippery snow covered roads that had me worried. Luckily (or unluckily) Cleveland use lots of salt and is good about plowing so once it stops snowing the roads are ready for riding quickly.
Craig