U .S. weather officials say December's wild El Niño pushed 2015 to near-record levels for heat, moisture and downright extreme conditions.
The National Oceanic and Atmospheric Administration announced Thursday that last year was the second warmest and third wettest in 121 years of record keeping for the lower 48 states.
The 54.4-degree average last year was second only to 2012.
Scientists blame a combination of man-made climate change and El Niño, the natural warming of the central Pacific that changes weather worldwide.
The U.S. set the record for warmest and wettest December, beating the old monthly warm temperature mark by nearly a degree.
NOAA said its extreme-weather index ranked 2015 as the most extreme year on record.
Global figures come out later, but 2015 will likely rank as the hottest.
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