Watch out for the steel transition joints on bridges/ramps. Especially if it is curved. Those things are like ice. I was going around a curved one once at the speed limit. I started out in the far left side of my lane, when i finally came out of the curve i was at the far right. Nice little wwoooooow at each joint.

When the rain is light it can suck because it will stick your visor. Heavy rain is better, sheets right off. Everyone else will be doing 45 in a 60 because they can't see and you CAN be cursing along at 80. I do not condone doing that, but i've done it a few times now on causeway. With good tires and good tread, hydroplaning is hard. But oily roads will take you out in a heartbeat. Intersection are the worst when it comes to the road being oily. Also as you may guess. Rail Road crossings are worse then the steel transitions. God do i hate crossing them in the wet.