I wear rain pants made by Mountain Hardwear if it's too cold to get wet. They have long zips down around the ankles and velcro to pull hold them snug and keep them out of the chain. They are thin and light and fold up nicely for storage. They are also long enough for my long legs. They don't breathe, but I prefer warm sweat to cold rain.
The first 2 days this week it was in the 30s (F) and raining really hard. Already well worth the $95 or so I paid for them when I got them last spring.