Sweltering September Sets Global Records

September 2015 was not only the hottest September on record for the globe, but it was warmer than average by a bigger margin than any of the 1,629 months in the records of the National Oceanic and Atmospheric Administration — that’s all the way back to January 1880.

The month continued a year of temperature superlatives that have 2015 virtually a lock to be the warmest year on record, topping the previous record set just last year.

While a major El Niño event is doing some of the heavy lifting in boosting global temperatures this year, such records are also a sign of how much Earth has warmed due to the continual buildup of heat-trapping greenhouses gases in the atmosphere.  That background warming tips the dice in favor of such heat records.

This September came in at 1.62°F above the 20th century average of 59°F, NOAA announced Wednesday, making it the warmest September in the agency's 136-year record.  (NASA, which assimilates global data slightly differently, ranked it the second warmest September.)  That’s the biggest departure from average for any month of any year in the record books.

The previous record holders in that category were February and March of this year, said Jessica Blunden, a climate scientist with ERT, Inc., at NOAA’s National Center for Environmental Information.  They were both 0.89°F hotter than average.

And it doesn’t stop there:  “Even more noteworthy is that six of the 10 highest temperature departures from average have occurred in 2015,” Blunden said in an email.

Read more at Sweltering September Sets Global Records