A United Nations weather agency report found the global mean surface temperature in 2011 was 0.4C above the long-term average, making it the eleventh warmest year on record.
This took the world's mean surface temperature to its highest point in a year that La Nina, a natural weather phenomenon that has a cooling influence, was strong.
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The World Meteorological Organisation (WMO) released the new figures on Friday (European time) to coincide with World Meteorological Day.
Professor Matthew England, who advises the federal government's Climate Commission, said it was "gravely concerning" that global temperatures continued to rise.
"The hotter temperatures and the extreme weather events across the world are consistent with our understanding of how the climate is changing," Professor England said in a statement.
The report found that Australia had its second wettest year on record, with rainfall 52 per cent higher than normal.
Cyclone Yasi, which ravaged northern Queensland early in the year, was the biggest contributor to the drenching.
The cyclone was the world's most intense landfall cyclone in 2011 and Australia's most intense landfall cyclone since 1918, WMO said.
"In Australia we can expect the quintessential cycle of intense droughts and flooding rains to continue," Professor England said.
Meanwhile, mean annual temperatures were 5C above normal in parts of the Arctic coast.
Arctic sea ice cover was well below average in 2011, with the second lowest seasonal minimum, the report said.
The US broke a number of heatwave records, including the highest mean summer temperature recorded and records for the number of days above 37.8C.
