September was second warmest for the globe and U.S.; 2015 likely headed for the record books

Month-by-month variation of global average temperature from the long-term mean. The first two frames of the animation show 1901 - 1950, and 1951 - 2000, respectively. The third frame shows 2001 through September of this year. Each colored box represents a specific month. V denotes major volcanic eruptions. (Graphic: Makiko Sato, Columbia University; Data: NASA/GISS; Animation: Tom Yulsman) This past September was the second warmest on record for the globe, according to numbers just released by NASA. Only September of last year was warmer in NASA's record, which dates back to 1880. And that was an extraordinarily warm month for the planet. (NOAA will soon issue its own independent analysis of global temperatures during September.) Meanwhile, the contiguous United States is really starting to heat up, with September coming in as the second warmest in a record spanning 121 years, according to the National Centers for Environmental Information. By comparison, August 2015 was much cooler in the lower 48 states, coming in as 31st warmest on record.