I would recommend trying different sizes as the fit across the Rev it range can vary. I am a slim build, 40 chest 5 9 and bought the size M. It is a snug fit with the thermal lining in, I would wear the removable waterproof layer on top of the jacket as required. The zips are chunky and the build quality is great. Highly recommend this jacket and a great price to boot from Sportsbike Shop.