Combined global temp. for May 2016 rose 0.87°C above the 20th century average
The combined average temperature over global land and ocean surfaces (SST) for May 2016 was the highest for May in the 137-year period of record, at 0.87°C (1.57°F) above the 20th century average of 14.8°C (58.6°F), besting the previous record set in 2015 by 0.02°C (0.04°F). May 2016 marks the 13th consecutive month a monthly global temperature record has been broken—the longest such streak since global temperature records began in 1880. —NOAA
Land. The average global temperature across land surfaces was 1.17°C (2.11°F) above the 20th century average of 11.1°C (52.0°F)—the third highest May temperature on record, behind 2012 (+1.26°C / +2.27°F) and 2015 (+1.21°C / +2.18°F).
SST. The May globally-averaged sea surface temperature was 0.76°C (1.37°F) above the 20th century average of 16.3°C (61.3°F). This was the highest for May on record, besting the previous record set in 2015 by 0.05°C (0.09°F).
January – May
The average global land and SST for January–May 2016 was the warmest on record across the world at 1.08°C (1.94°F) above the 20th century average of 13.1°C (55.5°F), surpassing the previous record set in 2015 by 0.24°C (0.43°F).
Much-warmer-than-average conditions engulfed the vast majority of the world’s land surfaces, resulting in a record warm January–May period at 1.85°C (3.33°F) above the 20th century average of 6.0°C (42.8°F), besting the previous record set in 2015 by 0.45°C (0.81°F).
The average global SST for the year-to-date was the highest for January–May in the 137-year period of record, at 0.80°C (1.44°F) above average surpassing the previous record set in 2015 by 0.16°C (0.29°F). Record warm sea surface temperature during January–May 2016 was present across much of the Indian Ocean and Southwest Pacific Ocean, with scattered areas across the Atlantic Ocean and the tropical Pacific Ocean.
NOAA National Centers for Environmental Information, State of the Climate: Global Analysis for May 2016, published online June 2016, retrieved on June 16, 2016 from http://www.ncdc.noaa.gov/sotc/global/201605.