Globe had 2nd warmest year to date, 4th warmest September on record --Arctic and Antarctic sea ice coverage remains small | 18 Oct 2017 | The average global temperature set in September 2017 was 1.40 degrees F above the 20th-century average of 59.0 degrees, according to scientists from NOAA’s National Centers for Environmental Information. This average temperature was the fourth highest for September in the 1880-2017 record. This marked the 41st consecutive September and the 393rd consecutive month with temperatures above the 20th-century average. The year-to-date average temperature was 1.57 degrees F above the 20th-century average of 57.5 degrees. This was the second warmest for this period, 0.23 of a degree behind the record set in 2016.