The Augusts of the 1920s were generally poor months and at times particularly cool, whilst the Augusts of the 1930s tended to be warmer with notable heatwaves
1920s decadal August average: 15.0
1930s decadal August average: 16.3
Number of days with a daily CET mean of 20.0C+

1920s: 1
1930s: 17
There was only one August in the 1920s that breeched the 16.0 CET mark: (1926: 16.2)
There were 7 August in the 1930s that breeched the 16.0 CET mark and 2 that breeched the 17.0 CET mark (1932: 17.1; 1933: 17.6)
The Augusts of the 1930s tended to be drier as well
1920s August rainfall average: 89.9mm
1930s August rainfall average: 65.9mm
There were no sub 50mm Augusts in the 1920s, there were 4 in the 1930s.

Dreadful Augusts that decade with a sunshine average comparable to the past 10 years though August 1930 was even worse - the wettest of the century here. 1933, 1934, 1936 and 1938 were all good Augusts though whereas only 1926 was passable in the 1920s.

The 1920s in general were an awful decade. The closest period in the past to the year round perma-autumn conditions we endure nowadays. Mid-1922 to early 1925 was particularly grim with three dire summers in a row followed by near snowless winters. 1923 and 1924 were two of the wettest years on record, both seeing remarkably similar conditions to the horror show that has been 2016 so far.