The combined average global land and ocean surface temperatures for May 2009 ranked fourth warmest since worldwide records began in 1880, according to an analysis by NOAA’s National Climatic Data Center in Asheville, N.C.
The analyses in NCDC’s global reports are based on preliminary data, which are subject to revision. Additional quality control is applied to the data when late reports are received several weeks after the end of the month and as increased scientific methods improve NCDC’s processing algorithms.
The May 2009 combined global land and ocean surface temperature was 0.95 degrees F (0.53 degrees C) above the 20th century average of 58.6 degrees F (14.8 degrees C).
Separately, the global land surface temperature was 1.19 degrees F (0.66 degrees C) above the 20th century average of 52.0 degrees F (11.1 degrees C), the eighth warmest for May on record.
The global ocean surface temperature was 0.86 degrees F (0.48 degrees C) above the 20th century average of 61.3 degrees F (16.3 degrees C), the third warmest for May on record.
For the year to date, the global combined land and ocean surface temperature of 56.5 degrees F (13.6 degrees C) tied with 2003 for the sixth warmest January-May period on record. This value is 0.97 degrees F (0.54 degrees C) above the 20th century average.
Other Global Highlights
Sea surface temperatures in the equatorial Pacific Ocean during May continued to increase for the fifth month in a row, supporting the presence of ENSO neutral state.
Arctic sea ice covered an average of 5.17 million square miles during May. This is 1.6 percent less than the 1979-2000 average extent. By contrast, Antarctic sea ice extent in May was 6.6 percent above the 1979-2000 average. Since 1979, May Arctic sea ice extent has decreased by 2.5 percent per decade, while May Antarctic sea ice extent has increased by 2.1 percent per decade during the same period.
Based on NOAA satellite observations, Northern Hemisphere snow cover last month was the seventh lowest for May in the 1967-2009 period of record. The Northern Hemisphere snow cover extent was 0.73 million square miles below the 1967-2009 average of 7.8 million square miles.
NOAA understands and predicts changes in the Earth’s environment, from the depths of the ocean to the surface of the sun, and conserves and manages our coastal and marine resources.