Mapped: Where in the UK are temperatures set to hit 34C?

Parts of southern England are set to bask in a fourth heatwave this week, with temperatures set to reach highs of 34C.

An amber heat alert has been issued from 9am on Tuesday to 9am on Friday for the East and West Midlands, the south-east, south-west and east of England, as well as Yorkshire and the Humber.

The UK Health Security Agency (UKHSA) issued a warning of possible “significant impacts” on health and social care services, including a rise in deaths among the elderly or people with health conditions, and an increase in drownings.

Since May, three heatwaves have already been recorded across the country with temperatures breaking records in June, as the UK faces more extreme weather fuelled by human-caused climate change.

On Wednesday, temperatures are set to reach 33C in London and surrounding counties, with highs of 25 degrees recorded in Manchester and 26 degrees in Cardiff.

The hot weather will continue into Thursday but will remain cooler in the North, with highs of 19 degrees recorded in Belfast and 18 degrees in Glasgow.

Forecasters are expecting this week’s heat to be a “North-South split”, with clouds and outbreaks of rain continuing in Northern Ireland, Scotland and northern England.

But the peak will be “almost a blink and you miss it”, with temperatures widely cooling close to average by the weekend, said senior Met Office meteorologist Dan Stroud.

July was 3C above average across the UK, according to provisional Met Office data.

This could put it among the hottest three or four months of July on record, said senior Met Office meteorologist Dan Stroud. Some parts of the UK had rain over the weekend, mainly in the North and North West, with 33mm (1.3in) falling on Sunday at Charterhall, in the Scottish Borders, and Altnahinch Filters in Co Antrim, Northern Ireland, receiving 17mm (0.7in).

But mainly places missed out and stayed largely dry, the Met Office said, with little, if any, relief in some southern regions.

Some spots have gone for weeks without rain – such as Wisley in Surrey, which has had 40 consecutive dry days.

The heat and ongoing dry conditions have led to hosepipe bans for 23 million customers, while even water companies without bans in place are telling households to conserve water, and drought has been declared across a swathe of Wales.

Southern England has had just 1 per cent of its average July rainfall. England has had 5 per cent and the UK as a whole 20 per cent, according to the Met Office.

However, the forecaster warned that heatwave thresholds will need to be adjusted to take into account the warming climate, with fire chiefs also warning of the additional risk of wildfires.

At the height of the third heatwave, in mid-July, firefighters were battling 19 significant wildfires simultaneously in England and Wales.

A National Fire Chiefs Council (NFCC) spokesperson said: “With the Met Office warning that a fourth heatwave could develop this week, bringing another period of very hot weather to parts of the UK, fire and rescue services remain on alert and are continuing to prepare for renewed wildfire risk.”

Southern England has had just 1 per cent of its average July rainfall. England has had 5 per cent and the UK as a whole 20 per cent, according to the Met Office.

The dry spell has contributed to low water levels, and north Wales and the Upper Severn became the first part of the UK to declare drought status on Thursday.

In addition, fires, if they start, are likely to become exceptionally severe on Wednesday in pockets of the East, South, and south-east England, according to Met Office data used by Natural England and Natural Resources Wales.

The “exceptionally severe” warnings focus on eastern England on Thursday.

Met Office chief meteorologist, Dan Suri, said: “After a prolonged spell of hot, dry and settled weather, some will see a temporary change this weekend as weather fronts move south-east across the UK.

“While some areas, particularly in the North and West, will see rain and showers, many places are likely to receive relatively little rainfall.

“For much of southern England, dry conditions are expected to remain the dominant feature, with temperatures recovering quickly next week and the potential for very warm or locally hot weather to return.”

Met Office five-day weather forecast

Tuesday

Outbreaks of rain continue across northern areas, with some heavy bursts possible in Northern Ireland and western Scotland. Elsewhere, it stays dry with sunny spells. The sunniest conditions are expected in the South, where it will feel hot and humid.

Tuesday night

Cloudy across the North West, with a chance of rain. Dry across much of England and Wales with clear spells, and a few isolated mist and fog patches. Another warm night.

Wednesday

Rather cloudy across the North, with outbreaks of rain sinking southwards into northern England during the afternoon. Dry and sunny across the South, where it will feel hot and humid.

Thursday to Saturday

Thursday will be fresher with sunshine and perhaps the odd shower. Mostly dry on Friday and Saturday with further sunshine developing at times. Still warm in the sunshine.