In reply to Prof. Outdoors:
I've been having this whole discussion with my wife, who now has a 7 mile bike commute, at least twice a week.
I said don't go for waterproofs, you'll just get wet from the sweat. She was not convinced, but has bought, from decathlon, a cycling poncho, to be used on top of her Decathlon cycling top when needed.
Are they a good compromise, waterproof from above at least put presumably plenty of air from below?