There was a short intense heatwave during the first week of June 1996, where maxima got as high as 33.1C in London on the 7th, however by that Friday evening, some really severe thunderstorms developed and the worst affected areas was an area from Weymouth to western parts of Norfolk. Golf ball sized hail fell widely in this area and in an area from south Oxfordshire to west Berkshire, rainfall totals exceeded 40mm. Lightning was widely seen across England in one of the most brilliant and widespread displays of recent times.
In Manchester, the Friday was clear and not especially hot but during the evening heavy rain and thunder suddenly spread up from the south. Quite a turn around from during the day.
7th June 1996 heatwave
St James's Park: 33.1C
Gravesend, Wattisham: 32.9C