Rain gear is only useful to me if it's cool to cold. Under 60F For summer many including myself will argue that you are already set. Fenders and a cover or waterproof bag for your stuff is all you need. I add a hat with a brim helmet to stave off drops in my eyes, but that's it. If it's warm I am going to get wet either way as no rain gear will keep up with my sweat output. And I am waterproof as it turns out.

As a year round commuter I have collected 3 different weight rain jackets/pants combinations to choose from. cool, cold, and super cold. Add layers, lather, rinse, repeat.