There's been the odd occasion when wearing the rain coat has caused me to sweat too much, but normally, if it's raining more than a drizzle, it's a net positive. This morning, the coat was soaked by the time I got to work, while underneath I was just slightly damp from perspiration. Mostly I find that rain in Edmonton is very cold, so even in situations where I'm not dryer, I'm still more comfortable. When I've traveled to warmer climes, this has been less significant.

The worst thing, I find, is that the parking garage where I lock up is very humid, and warmer than it needs to be. So even if I ride in dry, my face starts to drip as soon as I ride in.