Last month was the globe's warmest November on record, the seventh consecutive month to reach a new high.
A climate update Thursday from the National Oceanic and Atmospheric Administration also noted a record-warm average temperature for January through November as a whole. NOAA scientist Jake Crouch said it's "virtually certain" that 2015 will be the warmest year globally since record-keeping began in 1880.
The agency also said it's been the warmest autumn on record for the continental U.S., with an average temperature of 56.8 F (13.8 C) for September through November.
Crouch said the warmth has come from climate change, a strong El Nino and some other short-term influences.
Climate change is primarily caused by the accumulation of greenhouse gases, or heat-trapping gases, in the atmosphere. Greenhouse gases are certain molecules in the air that have the ability to trap heat in the Earth’s atmosphere.