I average 4. There were certainly months this winter where it felt like I didn't ride 4 times with all the ice, but now that that is out of the way, it's 3 some weeks, 5 others. If I have a late class/work, I'll usually ride in then take the train home since my route home goes through a park that I'm not comfortable in after dark and there's no easy way around. I'll make exceptions for crappy weather--thunderstorms/hail, gusts over 35mph or so (unless it'll be a tail wind :) and take the train those days, but that also allows me to run errands that are hard to do on the bike. Also, if I have to dress up for something I'll usually take the train rather than try to get nice clothes to work looking unwrinkled....