My preferred method for calculating the global average temperature anomaly for HADCRUT4.6 is by triangulating the measurements over the surface of a sphere. This gives almost identical results to those of Cowtan & Way but is a far simpler and faster method. Here is my update for July 2018.
Here is the detail for the Northern Hemisphere
Finally here is the Southern Hemisphere (their winter) which shows cooler than normal temperatures over the tip of South America.