Lots of cyclists commute in dark and rain here in the Pacific Northwest, but they make sure they have serious lights, bright clothing, etc. My spouse is one of those. BIG front light, blinkie on helmet, bigger red blinkie on back rack, etc. If you feel well equipped visibility-wise, it can be and is done in these conditions. It sure is more of a risk. But it is done every day by folks. Not sure I would do it, myself.