The US National Oceanic & Atmospheric Administration says 2012 marked the warmest year on record for the United States.
The hot weather contributed to a record drought which at its peak parched 61% of the nation.
Eleven weather disasters that caused over $US1 billion in damage, including Hurricanes Sandy and Isaac and tornados in the Great Plains, Texas and the Ohio valley.
All 48 states in the continental United States had an above-average annual temperature in 2012.
