[1] A layer of mineral dust blowing north from the Sahara met cold, wet air over the British Isles, resulting in thick, dense clouds and severe thunderstorms across most of England and Wales.

[1] The warm desert air brought a heatwave over Southern England, with temperatures in London on 1 July measured at 32 °C (90 °F), until it met the much cooler, moister Atlantic airstream.

[7] Hailstones 75 millimetres (3.0 in) across – the size of a tennis ball – were measured at Cardiff Airport, and the local newspaper for Hartland, Devon, reported the finding of "a piece of ice 4 inches (100 mm) long".

[2][3][9] Hail broke windows and dented cars across a wide swathe of the country, and damage was reported at both Cardiff Airport and RAF Chivenor.

[10][11] The Met Office noted that many rivers across the West Country and the Midlands burst their banks, and said that every town and village in Devon was flooded, with damage to property and crops assessed as "a major disaster".