With unusually warm sea-surface temperatures over a vast expanse of the tropical Pacific dominating the winter, globally the first eight months of 2010 matched the warmest such period on record, dating to 1880.
The combined ocean-land surface temperature for Jan. 1-Aug. 31 was 58.5 Fahrenheit, according to the National Climate Data Center, putting it in a first place tie with the first eight months of 1998.
That was another year in which a strong warming event, or El Nino, had taken hold in the Pacific. Here is the climate center's global analysis.
In August Arctic sea ice was well below the 1979-2000 average and was at its second lowest level, behind 2007. By contrast, the August sea ice in the Southern Hemisphere was at its highest extent ever.