It'll be a mild start to the New Year with temperatures Monday climbing about 10 degrees above normal. The average high doesn't change much through the month of January, overall 29°-30° is the average high the first through the 31st. We can expect a little over 10 inches of snow through the month.
While we stay mild for the start of the week, unfortunately it won't continue for long. Between Monday and the end of the week we will notice an almost 40° temperature drop, and temperatures will go from 10° above average to 10-20° below normal.
The silver lining is that temperatures warmed enough at the end of December to melt off most of the 16 inches of snow we received in December. Because of that, it will be slightly warmer overall because the snow won't be around to reinforce the cold. Most of the country will feel the chill well as the Climate Prediction Center outlooks most of the U.S. below average through the 8th.