A man runs on the street in downtown Chicago, the United States, on Dec 9, 2015. The US National Weather Service said there is a 70 to 80 percent chance the average temperature in December will be above normal for the Midwest due to a strong El Nino. In Chicago, the average temperature is 27.7 Fahrenheit degrees in December and the average temperature in December this year could be 5 to 7 degrees above normal if current forecast models hold. [Photo/Xinhua]