Temperatures could rise to a balmy 26°C in parts of the UK next week, with experts warning water storage levels may be affected.

Southern areas are likely to see the highest temperatures, but the warmer weather is expected to be felt generally across the UK, with most places experiencing above-average temperatures for September.

This follows several months of heatwaves and drought conditions, and comes amid Met Office warnings of a “record-breaking” El Niño bringing wetter and stormier weather in the months ahead.

How hot will it get?

After a mostly cloudy start to the weekend for some, with outbreaks of rain across southern England, Scotland and Wales while the rest of the UK experienced some sunnier spells, Sunday was forecast to bring drier conditions, particularly in the south.

Bouts of sunshine were forecast on Monday and Tuesday, together with generally warmer conditions across the board due to an area of high pressure. A brief spell of rain is expected to move into the north on Wednesday, but conditions will continue to stay dry for many.

Temperatures could peak at around 25°C or 26°C in south-east England towards the middle of the week, forecasters said, hovering around the low-20s in many other parts of England, Wales, Northern Ireland and Eastern Scotland.

How long will the warm spell last?

While the rise in temperature may last all week in some parts of England and Wales, the Met Office advised that it might only be a temporary flash in the pan for Scotland and Northern Ireland.

Grahame Madge, climate spokesman for the Met Office, said: “On Monday and for the early part of next week, we are forecasting a warmer spell with temperatures in the mid-20s for parts of the UK.

“However, this will likely be a relatively short-lived event and isn’t expected to achieve heatwave conditions.”

How will the warmer weather affect droughts?

While the sunnier weather may come as a pleasant change for some, it is likely to have a negative impact on the UK’s declining reservoir and water storage levels.

After a summer of record-breaking heatwaves, the Environment Agency has warned the country will need above-average rainfall throughout autumn and winter for most areas to be out of drought by April 2027.

According to the agency, there is a one in four chance that six regions of England will still have drought status by spring if the country receives 80 per cent of typical rainfall.

Environment Agency chief executive Philip Duffy said: “The drought situation remains very serious, and we cannot underestimate the challenge ahead over the coming months.

“Several reservoirs are concerningly low. Water supplies are limited and we continue to balance the needs of agriculture, public water supply, and our environment.”

Duffy urged everyone to “use a little less water to speed up drought recovery”.

How will El Niño affect the UK?

Alongside the ongoing droughts, the UK may soon also feel the effects of a “record-breaking” super El Niño, potentially bringing “stormier” conditions and severe flooding.

The Government has already warned that this year’s “supersized” El Niño could threaten global food supplies due to the extreme weather patterns it creates.

El Niño is the biggest fluctuation in the world’s climate system, known as the El Niño-Southern Oscillation (Enso) cycle.

Typically occurring once every two to seven years and lasting nine to 12 months, an El Niño event is declared when sea temperatures in the tropical eastern Pacific rise 0.5°C above the long-term average, with varied effects on rainfall patterns and temperatures across the globe.

A “super El Niño”, meanwhile, is broadly defined as when tropical Pacific Ocean surface temperatures reach 1.5-2°C, or more, above average. These events are rare: there have been only five since 1950, with the most recent occurring in 2015-16, resulting in 2016 becoming the hottest year on record at that time.

Madge said: “El Niño is developing rapidly in the tropical Pacific and is soon to become a record-breaking event, surpassing the strength of previous El Niños.

“Globally, there have already been impacts from El Niño, for example, reductions in rainfall in the South Asian monsoon.

The Met Office spokesman added that a stronger El Niño creates a “tendency towards stormier and wetter conditions in late autumn and early winter, and a trend towards colder spells in late winter.”