Very hot but a strongish cooling breeze. The barometer fell 15 or 20 mb during the day despite the hot weather and sunshine (lots of cirrocumulus though) and thunder reached Wimbledon at 7 pm, with noticeable medium-wave hissing at 7.30.

By 8 pm it was clear something was going to happen, there were rumbles at 8.30 and from 8.45 or 9pm to 9.40 or so a huge thunderstorm raged, passing right over the house. There were very strong downdraught gusts (65 mph according to a later severe weather warning), very heavy rain and prolonged flashes of lightning and crashes of thunder.

'Violent thunderstorms on the 24th over the southeast as a cold front moved east. Lightning damage and death.' [...]