Back on October 18, NOAA released their winter forecast. There was nothing too exciting for Illinois. Illinois has equal chances of above, below, and near-normal temperatures. The same is true for precipitation, except along the westward edge of Illinois which has a slightly increased risk of below-normal precipitation. See maps below.
If you look at the past dozen years in Illinois, winter-time temperatures have been consistent at being inconsistent (see graph). We have had some really mild winters in 2001-2002 and this last winter. On the other hand, we have had harsh winters including the three before this last winter.
Just to give you an idea of what is “normal” or average about Illinois, here is the link to the monthly and seasonal precipitation, temperature, and snowfall across Illinois.