Here's what the day was like (and I quote):
Notably cold, with severe thunderstorms for some.
The weather pattern was very disturbed. Bank Holiday Monday was a notably poor day - regarded at the time as 'one of the worst on record'! The day was dominated by a cool northerly airflow (though it's strength had eased from the previous days). There were some spectacular (& slow-moving) thunderstorms, with large hail and some 4ft (over 1m) of water causing flooding in Tunbridge Wells (Kent). The storm started mid-morning, with heavy rain and the hail started just before midday. At one point, the centre of the town was buried under a foot (~30cm) of hail-ice, with drifts of hailstones up to 4ft (~1m) deep. In other areas, 62mm of rain fell in one hour at Swanage (Dorset) & Arundel (Sussex); 80mm of rain at Faversham (Kent). The midday temperature in central London was just 13degC (c.f. the average day maximum of 22degC). On this measure, it was regarded as the coldest Bank Holiday Monday in the capital since 1880. [ This August was one of the coldest and wettest of the 20th century. ]
But meanwhile, up in the north, maybe the weather wasn't quite so bad?
It's also (moderately) interesting that the August Bank Holidays back then were at the beginning of the month rather than, as now, at the end.