According to the Japan Meteorological Agency, “The monthly anomaly of the global average surface temperature in August 2015 (i.e. the average of the near-surface air temperature over land and the SST) was +0.45°C above the 1981-2010 average (+0.79°C above the 20th century average), and was the warmest since 1891. On a longer time scale, global average surface temperatures have risen at a rate of about 0.65°C per century.”

See graphic above.