Over the next few days, the UK will hit the country with tropical weather with “sultry” conditions bringing a mixture of 29C heat and rain.
Heavy showers are coming from the Atlantic Ocean will ravage parts of the country this weekend, while southern and eastern areas will be hot and humid, forecasters say.
Thunderstorms could rumble before temperatures reach the high 20s from Monday.
With Office forecaster Tom Morgan told the PA news agency: “The main theme for the coming days will be wet weather, in stark contrast to the rest of July.
“Many areas will be very hot and humid with a lot of cloud cover, even at night, with temperatures reaching 20°C in the early hours, meaning uncomfortable nights for sleep ahead.
“In remote areas, a strange rumble of thunder may be heard, and it will be quite muggy and humid, typical of conditions in tropical countries.
“Daytime temperatures can reach 29C in southern areas, but it will feel uncomfortable and clammy.”
He said “humid” air from the southwest will enter the Atlantic Ocean, where sea temperatures are above average.
About 30 to 40mm of rain could fall on Monday and Tuesday in northern, central and western areas, but “nothing too disturbing” and “useful for farmers and gardeners”.
Morgan went on to say it will be a “week of two halves”, with cooler and drier weather starting Wednesday.
He added: “The rain will clear up and there will be a less cluttered picture, with calmer conditions and temperatures around 20 degrees.”