As much as I hate it, I'm going to try this year because I actually have the MTB now.
Monday was tough, though. Mid 20s, snowing, and 18-20 mph winds. I went for 37 miles and found out I need new gloves. My gloves are fine in the 30s, but the 20s killed them.
I definitely ride a lot less, though. I do a lot of 12 mile rides, which is to the end of the bike path and back (the bike path may suck, but it's empty this time of year). My theory is that I can tolerate any kind of weather for an hour or less.