When we say waterproof, we mean waterproof, not showerproof, or weatherproof, or something else. Waterproof means waterproof, which means you can go out in the rain and not get wet.

When we say windproof, we mean.... Okay, I think you get the idea. But, seriously wind chill is not funny, stopping wind penetration will mean you stay a lot warmer than you would in a shorter coat.

Waterproof fabrics are great, but breathable ones are better. Breathable fabrics allow sweat in the form of water vapour to escape from the inside of the fabric to the outside, which is great if you plan to spend a long time in your coat or like to walk fast.