Wet weather and scorching temperatures propelled the United States into record books for the hottest December in modern history and the second warmest year since the late 1800s, US government scientists said Thursday.

The report from the National Oceanic and Atmospheric Administration is the latest to document a warming trend that many scientists expect will make 2015 the planet's steamiest year on record.

Man-made climate change resulting from the burning of fossil fuels, along with the El Nino weather phenomenon have combined to wreak havoc in much of the world's weather, scientists said.

"It was quite an exceptional month," said Jake Crouch, climate scientist at NOAA's National Centers for Environmental Information.

December 2015 marked the first time in 121 years "that a month has been both the wettest and the warmest on record," he added.

For the United States alone, December 2015 was "record warm for the contiguous US, with a temperature of 38.6 Fahrenheit, six degrees above the 20th century average," said the NOAA report.

Temperatures soared past the last record-breaking December, which was in 1939.

The additional precipitation can be blamed in part on the El Nino trend which can heat up the equatorial Pacific and cause heavier rains in some parts of the world, scientists said.

"The December precipitation total for the contiguous US was 3.93 inches (10 centimeters), 1.58 inches (4 cm) above the 20th century average," it said.

The average temperature for the entire year in the United States was the second warmest since record-keeping began in 1895.

Only 2012 was warmer, NOAA said, noting that 2015 marked the 19th year in a row that the annual average temperature exceeded the 20th century average.
According to Crouch, four states experienced their hottest years on record -- Florida, Montana, Oregon and Washington. No state was unusually cool.

"Every state had an above average temperature for the year," said Crouch.

The NOAA report also said there were 10 weather and climate disaster events that caused losses above $1 billion each.

"These events included a drought, two floods, five severe storms, a wildfire event and a winter storm," and resulted in 155 deaths.

Extreme weather events happened 70 percent more often than average last year, ranking as the fourth highest annual US Climate Extremes Index in the 106-year record, the NOAA report said.

Global climate data for 2015 is to be released on January 20.

Worldwide, nine months this year have broken heat records for global temperatures across land and sea surfaces, including the last seven in a row, NOAA said in its last report of 2015, issued in December.

Only an unusually cold December would prevent the planet from breaking new heat records for 2015, Crouch said.