Unless you are in a torrential downpour, water resistant is probably what you want rather than waterproof. Water will bead up and roll off a water resistant garment. If you aren't sure, you can always test the water resistance of your coat at home by misting it with water, and watching for the beading. If the water resistance wears off due to laundering or cleaning, you can re-treat it yourself with one of those spray cans.
It may not be fashionable, but a hooded coat may be practical in a storm not only by protecting your head (which a hat would do) but by preventing water from running down into your collar. Some rain coats have hoods that roll up (not may favorite) and some have collars that button onto the coat underneath the outside of the collar (looks better, but could get lost if you don't store both together).
That's way more information than you asked for, so I'll stop now.