Every weekday. It's how I get home. In the mornings I bus, but home it's on bike, rain, shine, 30 degrees or 100. There's some acclimation. The first really hot day can take it out of me, but like most things, you get used to it, especially if you have no choice. My wife has always been a fair weather biker -- if it's over 80, she bows out, but lately the AC in her car has been out, so she's been forced to deal with the heat whether she wants to or not. As a result, he acceptable bicycling range has gone up as well.