The high temperatures could bring some welcome relief from heavy thundery downpours that are expected in parts of the country, according to the Met Office.
A Met Office forecaster said it would be a wet start to the week for some, with a yellow weather warning of rain in place over the end of the weekend for western Scotland, Northern Ireland and parts of northern England.
This could lead to some localised flooding and travel disruption, they added.
Temperatures will reach 28C in southern England from Monday, which will see a dry and bright start to the week.
“As we head through the week, the rain will generally begin to ease across northern areas, so the potential is for much of the UK to see some hot conditions,” the Met Office spokesperson said.
“There will be some sunshine around during the week, but also the risk of some heavy thundery downpours as well.”
Temperatures will increase as the week progresses, according to forecasters, reaching highs of 33C on Tuesday and 34C on Wednesday.
Although the main concentration of the hot weather will be in central and south-eastern England, parts of Scotland could reach the high 20s.
For the majority of the UK, the mercury needs to hit 25C for three consecutive days to be classed as a heatwave.
This threshold increases further in the southeast in the country, with temperatures in London needing to reach 27C.
The maximum temperature recorded in July is 36.7C (98F), on the first day of the month in 2015 at Heathrow.
Looking ahead to next weekend, the Met Office expects temperatures to fall.
“There’s some uncertainty though on just how long the heatwave conditions will last for,” the forecaster said.
“It looks most likely that, at least by Saturday, most areas will see a bit of a drop in temperatures.
“There’s still a lot of sunshine around for the weekend and temperatures probably look to be not quite as hot, but with a summery feel staying for the weekend.”
Additional reporting by Press Association