Seriously folks, if you're on a bike, wear your helmet. I had a little bike accident on Friday night. I was wearing my helmet and I was glad I was. I have no dramatic photos of bruises or skinned knees for you. Most of my aches and pains from the accident are internal (my neck is still out of wack. Chiropractor, here I come!). But I did hit my head and my helmet had a chance to do what they're supposed to.
See, that's the thing about accidents, you can't plan them. You can't decide that you'll always land in such a way that you won't hit your head. They happen so fast, without warning. So, really. Be safe. Wear it. It doesn't matter if it's too hot or if you're just going to be on the bike path. For what it's worth, the worst bike accident I've ever seen was on the bike path, between a cyclist and a pedestrian. Both were taken away in ambulances. Wear a helmet, because you never know when you'll need it.