Extreme heat and drought are expected in the southern half of the UK this weekend, while the northern half will be hit by thunderstorms and flooding.
The With Office has issued an orange heat warning for most England and Waleswhere temperatures of up to 34C are forecast for Saturday and Sunday.
This means that heat-related illnesses, including sunburn and heat exhaustion, are “likely” among the general population, and public transport delays are “possible”.
Meanwhile, a yellow warning for lower-level thunderstorms applies for most of Sunday from noon to 6 a.m. Monday. Scotland and Northern Ireland.
This warning means there is a “small chance” of flooding in these countries and the possibility of power outages.
The highest predicted daytime temperature of 34C is forecast in the south east on Saturday, with 32C forecast in London and 27C in Edinburgh.
Further north in England, temperatures around 30°C are expected, while much of Scotland and Northern Ireland can expect temperatures in the mid-twenties.
This comes after an official drought was declared Friday in eight areas of England by the National Drought Group (NDG), which includes representatives from the government, water companies, the Environment Agency (EA) and others.
Firefighters in Derbyshire were still fighting a massive blaze at 9pm on Friday night, with four fire engines on the scene in Creswell, Worksop.
Images shared online showed flames filling the horizon and large plumes of smoke in the sky over a residential area.
Derbyshire Fire and Rescue Service also fought embankment fires next to a railway line at Matlock, and near Junction 26 of the M1.
The agency said it was “planning a busy weekend” of further fires, and following pleas from fire services across the country, asked people not to build bonfires in the yard or use portable barbecues.
Some 35 firefighters were also deployed to fight a two-acre blaze in the Leyton Flats Game Reserve in Waltham Forest, east London.
The crews of the London Fire Brigade (LFB) were captured while engulfing the flames on the spot.
The agency said there were no ongoing fires in the capital as of 9 p.m. Friday.
In Dorset, firefighters have stayed up all night trying to bring a major fire in Studland under control.
Ninety firefighters were deployed when the fire was first reported at about 1 p.m. Friday, and 10 fire engines were deployed from adjacent areas, Dorset and Wiltshire Fire and Rescue Service (DWFRS) said.
A police spokeswoman told the PA News agency that a disposable barbecue was the most likely cause.
“We found evidence of a small camp where someone had used a disposable barbecue. We can’t say 100% that was the cause, but when we find evidence we have to assume it’s the most likely cause – fires don’t just start on their own,” she said.
Between August 1 and 10, DWFRS attends 180 wildfires, compared to just 34 in the same period last year – a 429% increase.
The spokeswoman said operational staff “has never had a year like this before, it’s just unprecedented.”
According to the EA, the drought in England could last until next year.
John Curtin, executive director of local operations at the EA, said it would take “weeks of rain” to replenish water sources after the driest summer in 50 years.
The announcement could lead to more measures, such as banning garden hoses, but the EA has reassured the public that essential water supplies are safe.
Eight of the 14 areas designated by the EA have now been moved to “drought”, the second phase, including Devon and Cornwall, Solent and South Downs, Kent and South LondonHerts and North London, East Anglia, Thames, Lincolnshire and Northamptonshire, and East Midlands.
Three water companies – Welsh Water, Southern Water and South East Water – have all imposed bans on garden hoses, while Yorkshire Water has announced a ban will come into effect on August 26 and Thames Water is planning one in the coming weeks.