Globally August 2017 was the second warmest August since reliable measurements started in 1880, 0.85C warmer than the 1951-1980 mean. The warmest August was in 2016 at +0.99C. (See the figure above.)
Compared to the 1880-1920 mean (which is also our best estimate for the pre-industrial average temperature) global temperature is now about +1.2C (see figure below). The warming rate since 1970 is 0.17C/decade.