As an active all season rider, and a fellow Sportster enthusiast, I have no problems anywhere. I rode through ankle deep flash floods, "in 10 seconds you get your underwear wet" thunderstorms, mud, sleek, slush, nor'easter in durations that stretch from half an hour to a couple of hours in local roads and highway speeds. My bike is new though (2012) maybe I am yet to figure out that "ooh, so if I submerge it then it does not work" type of situation. But, yeah, fear nothing. Make sure your plugs are covered, your battery is dry and off you go.
Until, someone much more experienced than I am speaks up and says "don't listen to the little rascal... " and gives sound, solid advice.