These are the actual sizes from the manufacture. Chest Size: XS 34, S 38, M 41, L 44, XL 47, XXL 52, 3XL 55.
I had to order the 'XL' which is a little big for me, but the 'L' would had been too small. The middle pull cord is hidden behind the fleece which makes it a bit of a problem to adjust. I've tried it in light rain and it seems ok. The coat doesn't breath, this means that it's soaking wet inside when you take it off. It is warm and seems to be waterproof.
The thing to note is that the size guide does not match with the manufacturers, so be careful when selecting the size.