I'm not sure there is ever a month when the sledding is 'usually good' in Illinois. This December had to be the best ever (?). Two years ago most of the local sledding was done in the 1st 10 days of March (2 8+ inch storms within 4 days of each other). January is the coldest month in IL, so it is warming up. My advice: anytime after January when we get a storm ditch work the next day and RIDE 'TIL IT MELTS! Now we are lucky if the snow is ridable for more than 3 or 4 days in a row.