I commute in the rain all the time. I've done all kinds of things to make it as comfortable as it can be. We don't really have a warm rainy season here in the Pacific Northwest... you can plan on lots of days with rain and temps in the 40's to low 50's. My latest addition to my commuter/rain bike is a BionX electric motor. So, even if it's wet, I can't complain about the riding being too difficult (pedal assist only, no throttle... but still, PAS level 4... a piece of cake.) My road bike doesn't have fenders... I don't enjoy riding it in the rain. Someday when I get bike N+1... I'll get a nice road bike that has fender mounts. Maybe this?:

Domane 6.2 Disc - Trek Bicycle