The NWS Climate Prediction Center released their latest outlooks for December, winter, spring, and summer. La Niña conditions are present and slightly favored to persist (~55% chance) through winter 2016-17. It is one of many players in our winter weather. Click to enlarge.
December
Illinois has equal chances (EC) of above, below, and near-normal precipitation and temperatures.
December-February
Illinois has an increased chance of wetter than normal conditions in the eastern two-thirds of the state. Above normal precipitation in winter typically translates into more snow.
March-May
Illinois has an increased chance of being warmer than normal in spring.
June-August
Illinois has an increased chance of being warmer than normal in summer.
Illinois State Climatologist 
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