Time to stop messing around with lesser raincoats and get the good one!
I've seriously never loved a raincoat more than I love my ~1980s Burberrys' trench. Look for one in 100% cotton, and don't pay more than $200. If you're a fan of a more vintage aesthetic (which you ought to be — we live in a very nostalgic time), you'll never be unable to style this coat for the rest of your life.
They're pretty readily available right now, but it'll be harder to find these older coats with each passing year. So go get yourself a classic Burberrys' trench in beige and be the coolest looking person walking home in a thunderstorm.