August was the month that the Spanish influenza epidemic of 1918 entered a second, deadlier phase after a new strain of the virus emerged. (PROSE: Casualties of War).
The Seventh Doctor, Ace and Bernice Summerfield arrived in Haiti in August 1915. (PROSE: White Darkness)
The Tenth Doctor noted to Reinette that this was not a very good month in 1727. (TV: The Girl in the Fireplace)