Be wary of potholes and ruts in the road that are hidden from view by water filling them during the rain. I crashed this morning riding into work when my front wheel fell into a rut and caused me to lose control. I was wearing sunglasses to keep the rain out of my eyes, but they greatly reduced my vision because of all of the water and road crap that was on them. ( detailed story here: http://www.bikeforums.net/showthread.php?p=8865852 )