While the United States was smashing heat marks last year, the world as a whole was among the 10 hottest on record, two U.S. science agencies said Tuesday.
Last year's average was 58 degrees Fahrenheit, the 10th warmest ever, the National Oceanic and Atmospheric Administration said. That's a degree above the 20th century average of 57 F.
The global average temperature for last year would have been a record 15 years ago, an indication that what used to be unusual heat is more commonplace.
The hottest year was 2010 when the world average temperature was 58.2 degrees. NOAA records go back to 1880.
"We're playing in a new neighborhood as far as global temperatures go, compared to even the late 20th century and especially the mid 20th century," said Deke Arndt of the NOAA.
La Niña, a weather pattern that generally cools the ocean globally, and mildness in Alaska, Canada, the United Kingdom and parts of Asia moderated the globe's average temperature. The Lower 48 states in the United States recorded its hottest year last year with an average of 55.3 F.
"In global warming, you expect warming to manifest itself in different locations in any given year," said Andrew Weaver, a climate scientist at the University of Victoria in Canada. "This year it was America's turn to feel the brunt of global warming's growing fury."
NASA, which measures temperatures differently, ranks 2012 as ninth warmest. It put the temperature at 58.3 F. Both agencies announced the data Tuesday.
Some global warming skeptics have claimed the world hasn't warmed in the past 16 years, but each decade is warmer than the last. Even the first three years of this decade were warmer than the last, the two agencies said. Since 1963, NOAA said, the global temperature has increased at a rate of 0.27 degrees Fahrenheit a decade.
Top 10 warmest years on record