Unfortunately, even the most breathable rain jackets and trousers can sometimes make for a sweaty cycle, so a rain poncho is an excellent choice for commuting unless there are some serioulsy high winds. They allow more air to circulate, so you won't get as sweaty and, since they mostly extend over your thighs, avoid the need for waterproof trousers too. Many also have thumb straps to keep the poncho where it's supposed to be, and cover your hands, so no need for gloves either!