It was the 36th consecutive June and 328th consecutive month with temperatures warmer than the 20th century average, NOAA said.
Across the globe, land areas were relatively warm compared to the oceans - in the midst of a transition from their cool (La Nina) to warm (El Nino) phase.
In the Northern Hemisphere, land areas were warmest on record for the third month in row - more than 2.34 degrees F above average.
While not at record high levels, the global average ocean temperature still ranked 10th warmest out of a pool of 133 years. In the Northern Hemisphere, the ocean temperature ranked 11th warmest.
Snow cover in the Northern Hemisphere, another indicator of temperature, reached its lowest extent in 45 years of June records (hat tip, Climate Central).
“Snow extent ... was more than 1 million square kilometers (386,000 square miles) below the previous record set in 2010,” said the National Snow and Ice Data Center:
[Running counter to Northern Hemisphere snow and ice indicators, Antarctic sea ice, was 2.5 percent above normal, 10th largest in the 34-year record. For quite a while, trends in Antarctic sea ice has gone against these global snow and ice indicators, likely linked to complex changes in ocean circulation in the region. Temperatures in that same region have warmed (see academic paper)]
For the year (January through June), global temperatures now rank 11th warmest on record. The greatest warmth, NOAA said, has concentrated over North America, southern Greenland, and Russia over these first six months.
But it hasn’t been warm everywhere.
“The first half of 2012 was notably cooler than average across Alaska, Mongolia, and Australia,” NOAA said.
Global warmth has generally increased as the La Nina event, associated with cool Pacific tropical ocean waters, has faded during the course of the year.
* January ranked 19th warmest
* February ranked 22nd warmest
* March ranked 16th warmest
* April ranked 5th warmest
* May ranked 2nd warmest
* June ranked 4th warmest