40º and rain sucks, 80º and rain is no big deal. Fenders keep the bike much cleaner, Brake pads and rims surfaces need to be cleaned after riding in the rain. Bike needs more frequent cleaning lubing, overhaul if ridden often in the rain. Even if your bag is "waterproof" put anything important in plastic bags. Painted road markings/stripes can be like ice when wet. glasses suck. road spray from cars sucks. Extra shoes so one pair can be worn while the other dries for a day or so. In the summer and warm temps I usually don't even bother with rain gear.