The UK has seen the hottest July day on record, with temperatures hitting 36.7C (98F).
The Met Office said the reading had been registered at Heathrow – breaking the previous record set in 2006.
A level 3 “heatwave action” heat-health alert has been declared for all parts of England.
But in Scotland, forecasters warned of thunderstorms, torrential downpours and hail stones up to 1cm in size.
“However, if one is experiencing minor difficulties, like a light migraine or headache, they should try rest, but keep fasting until sunset,” he said.
— Met Office (@metoffice) July 1, 2015
Muslims fasting for Ramadan might be suffering a lot in today’s heat, particularly seeing as observers avoid any fluids.
Shakyh Abdul Hussain of the East London Mosque told me that Muslims should always break their fast if they feel seriously ill, and seek medical attention. “However, if one is experiencing minor difficulties, like a light migraine or headache, they should try rest, but keep fasting until sunset,” he said.
The United Nations has urged countries to create better warning systems as a heatwave sweeping western Europe saw temperatures reach 40C.
In the west of France, in Brittany and the Pays de la Loire, there was a massive power cut which saw between 600,000 and a million homes left without electricity between Tuesday night and the early hours of Wednesday morning after high temperatures affected power equipment.
State authorities said it was “exceptional” for the weather to have such repercussions on power supply to homes.
Temperatures in Paris are expected to hit 39C on Wednesday afternoon, after south-west France saw temperatures of 42C and Córdoba in southern Spain recorded nearly 44C.