I commute in Portland OR, with headlamp and tail lamp on my helmet, so a helmet cover is out. I'd definitely pick the neon one, if I did use one. As it is, I simply wear a baseball cap under the helmet. It is water-resistant enough and the cap's visor works while the helmet's visor doesn't. When it is really raining, your glasses are getting wet no matter what. The cap also holds in heat better that the helmet alone, though when it is cold, I wear a thin balaclava too. We've had an easy winter so far, weird because La Nina was supposed to bring a wet, cold winter.