New York City is forecast to experience its coldest New Year’s temperatures since the 1960s. But Mr. Trump’s tweet made the common mistake of looking at local weather and making broader assumptions about the climate at large. The climate can be thought of, in a way, as the sum of long periods of weather. On Thursday, parts of the United States were roughly 15 to 30 degrees Fahrenheit colder than average for this time of year. But the world as a whole was about 0.9 degrees Fahrenheit warmer than the average from 1979 to 2000.

Source: New York Times December 29, 2017 01:43 UTC