Every month University of Alabama in Huntsville climatologists John Christy and Roy Spencer publish global temperature trend data derived from NOAA satellite measurements. Their latest analysis finds that January, 2016 was the warmest first month of the year since satellite data began to be reported in 1978. January's global average temperature was +0.54 degrees Celsius above the 30-year average (1981-2010) for the month reported. The next warmest Januarys occurred in 1998 (+0.49°C) and 2010 (+0.48°C).
Interestingly, warming has increased so much recently that Christy and Spencer also report that global average temperature trend since they last reported in December has now been bumped up from +0.11°C per decade to +0.12°C per decade.
Overall, the Northern Hemisphere temperature was +0.70 C (about 1.25 degrees Fahrenheit); the Southern Hemisphere was +0.39 C (about 0.70 degrees Fahrenheit); and the Tropics was +0.85 C (about 1.52 degrees Fahrenheit) warmer than the 30-year average for January.
In their notes, Christy and Spencer observed that, as was widely anticipated, "global temperatures in January set a record for the month, eclipsing January 1998 as the warmest January in the satellite temperature dataset. In a sense, that could mean 2016 is in a "race" to see if it will pass 1998 as the warmest year on record. In addition to a major El Niño Pacific Ocean warming event, 2016 has 17 years of warming to raise the base temperature from which the El Niño begins."
They additionally observed, "While the global temperature in January was a record setter, in the tropics January 2016 fell significantly (more than 0.25 C) short of the 1998 record. It could mean less energy is available to be transferred from the ocean into the atmosphere. It could mean the heat transfer might peak later this year than in previous El Niño years or might already be near its peak. What we know is that under the best of circumstances the climate system is complex and difficult to forecast. It will be interesting to see how this plays out in the coming months."
Go here to check out the monthly temperature data since 1978.