Last month was the hottest January worldwide since records began, the ninth consecutive month of record-breaking heat, the federal government said.
The average temperature across land and water surfaces was 55.47 degrees Fahrenheit, breaking the previous record set in 2007 by 0.29 degrees, the National Oceanic and Atmospheric Administration said Wednesday in its monthly temperature update.
2015 set an annual temperature record, beating the previous record set a year earlier.
Climate scientists have cited the rising temperatures as a key indicator of human-induced climate change. But the strong El Niño pattern that started developing last year has also fed into the heat.
The average temperature on land surfaces was 2.81 degrees Fahrenheit above the 20th-century average and was only the second hottest for January, according to NOAA.
But sea surface temperatures, at 1.55 degrees above the 20th-century average, were the hottest on record.