A monthly analysis of global temperature by a group of scientists at NASA revealed that last month was third warmest January in 137 years of recorded history. However, it was .20 degrees cooler than last year’s January (2016) which was the hottest in recorded history. January 2016 was 1.12 degree Celsius warmer than the January mean temperature followed by January 2007 with .96 degree warmer..

January 2017 was 0.92 degrees Celsius warmer than the mean January temperature from 1951-1980.
NASA’s Goddard Institute for Space Studies (GISS) came to the conclusion on the basis of a monthly analysis of publically available data gathered by about 6,300 meteorological stations around the world, ship- and buoy-based instruments .

NASA has additionally said that the results may vary in case of availability of additional data.
Modern global temperature record keeping began in 1880 as earlier observations did not cover enough of the planet.

The GISS upgrades its temperature charts and tables in mid of every month.
These graphs are updated using current data files that have reports for the previous month as well as late reports and corrections for earlier months.