Temperatures are set to hit 20C on Monday and Tuesday, and could soar to 23C in some parts of the UK on Thursday according to the Met Office.
"[Monday will be] cloudy with some light rain or drizzle at times in the east and the longest sunny periods reserved for Wales, western England and southwest Scotland," it said.
But by Tuesday and Thursday Brits will enjoy "dry [weather] with spells of sunshine."
The Met Office recently said this summer has been both cooler and wetter than average, despite a dry and sunny June, and warmer temperatures at the start of July.
"It'll be warming up particularly across the south of the UK towards the second half of the week," Tomasz Schafernaker, a meteorologist at the Met Office and BBC weatherman, said today.
"Temperatures could actually be rising from around Wednesday into Thursday. I think [they'll hit] at least 20 degrees on Wednesday, and by Thursday I wouldn't be surprised if [they] hit around 25C in one or two areas."