What clothing is best for wet weather/cycling in the rain?
Lightweight polyester or microfiber materials do the job. Pearl Izumi is my favourite. Bike specific rain jackets are a must if you are looking for comfort. Generally they are very thin and have air vents in them. There is no reason to wear heavy rain jackets. Instead, layer up up with a base layer (often merino wool or synthetic thermals) + mid layer + the shell (which is the jacket). That is probably the most common layup for cyclists and it will keep you warm.