Motorcycle Rain Jackets Rain jackets are useful in many situations, even in these days of waterproof climate membranes. Not only do they offer (additional) protection against the wet, they also keep you warm because they cut out the wind chill factor. On cold days, a rain jacket is a real bonus in terms of comfort and safety. If you're in any doubt, you can order two different sizes from Louis online and try them out. Louis will take back any item that does not fit or which you do not like.