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).
In August 1914, German troops were advancing on the Belgian town of Mons. The United Kingdom was preparing to enter World War I by defending Mons. (COMIC: The Weeping Angels of Mons)
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, warning her to "stay indoors". (TV: The Girl in the Fireplace)