As of 2014, 2013 tied with 2009 and 2006 for the seventh warmest year since 1880 according to NASA scientists. With the exception of 1998, the 10 warmest years in the 134-year record have all occurred since 2000, with 2010 and 2005 ranking as the warmest years on record. Earth continues to be hotter than it was several decades ago. 

This color-coded map shows how Earth's surface temperature has changed from 1880 to 2013. Higher-than-normal temperatures are shown in red and lower-than-normal temperatures are shown in blue. 

The average temperature in 2013 was 14.6 °C (58.3 °F), which is 0.6 °C (1.1 °F) warmer than the mid-20th century baseline. The average global temperature has risen about 0.8 °C (1.4 °F) since 1880, according to the latest (January 2014) analysis from NASA's Goddard Institute for Space Studies (GISS). Exact rankings for individual years are sensitive to data inputs and analysis methods.

While the world experienced relatively warm temperatures in 2013, the continental U.S. experienced the 42nd warmest year on record. For some countries, such as Australia, 2013 was the hottest year on record.

The temperature analysis done by GISS is compiled from weather data from more than 1,000 meteorological stations around the world, satellite observations of sea-surface temperature and Antarctic research station measurements, taking into account station history and urban heat-island effects. Software is used to calculate the difference between surface temperature in a given month and the average temperature for the same place from 1951 to 1980. This three-decade period functions as a baseline for the analysis. It has been 38 years since the recording of a year of cooler than average temperatures.

Source: NASA Goddard Space Flight Center Scientific Visualization Studio 

Credit

NASA Goddard Space Flight Center Scientific Visualization Studio