Cool yesterday, wet and cool today. Both days found me with a rear flat tire at the end of my shift. Yesterday I swung by the shop to purchase a tube (since I had destroyed my spare in a previous inflation debacle that I now believe was entirely my fault) and borrow their floor pump. Today, since it was obviously a slow leak, I used the frame pump to get home, then did what I should've done yesterday, and thoroughly inspected the tire. Sure enough, a 1.5 cm long sliver of metal had just barely made its way through the tire. Nothing like inflating a tire in the rain to remind you to be a little more exacting in your bike mainenance.