Every month University of Alabama in Huntsville climatologists John Christy and Roy Spencer publish the latest global temperature trend data obtained from NOAA satellites. For the month of December 2015 they report:
For the globe and the southern hemisphere, December 2015 was the warmest December in the satellite temperature dataset. It was the second warmest December in the northern hemisphere, and the third warmest in the tropics. …
The El Niño Pacific Ocean warming event continued to push temperatures to record highs in December, putting a record end to the third warmest year in the satellite temperature dataset, said Dr. John Christy, director of the Earth System Science Center at The University of Alabama in Huntsville. 2015 finished with an average temperature that was 0.27 C (about 0.49 degrees F) warmer than the 30-year norm. The warmest year on record is 1998, when the annual average temperature was 0.48 C (about 0.86 degrees F) warmer than normal. The five warmest years in the satellite temperature record are:
1998 +0.48 C
2010 +0.34 C
2015 +0.27 C
2002 +0.21 C
2005 +0.20 C
Ocean temperatures related to the El Niño Pacific Ocean warming event are falling, which in the short term should mean temperatures in the atmosphere will continue to rise: The eastern central Pacific cools as it releases heat into the atmosphere. There is a lag between the two, so the atmosphere should continue to see El Niño-influenced high (even record high) temperatures for the next several months. This is a pattern seen in most of the El Niño events during the past several decades.
Go here to see satellite temperature data by month since 1978.