Hard to tell. I have been on it and had very little snow. This year was pretty light in early to mid November. In 2011 it was pretty unpassable in Nov. Late October is your best bet I have always had pretty good luck.
Keep in mind it gets VERY cold at night. Have a plan and let people know where you are going. No body expects to break down,but it happens. I hate going to look for people not prepared for fast weather changes in the middle of the night .