Is another UK heatwave on the way in September?

While wet weather is forecast for many this week, some long-range forecasts are suggesting further dry and sunny spells in September.

Many of us have experienced the first bit of rain in around two months as the weather turned more unsettled on Tuesday.

This change in weather patterns will also bring lower temperatures through this week, perhaps falling to around 2 to 4C below the mid-August average.

The prospect of cooler weather has led to speculation about the possibility of another heatwave - the sixth of the year - developing in September.

It has been an exceptional summer so far with the Met Office saying it is likely to be the hottest on record.

Even with cooler conditions this week, the mean average temperature would need to be considerably below average for the last two weeks of August, to keep 2026 from surpassing the record set just last year.

The hotter-than-average summer with an increased likelihood of heat spikes and heatwaves was predicted by the Met Office and MeteoGroup - the BBC's weather data providers - back in June.

These seasonal forecasts looked at a range of weather patterns as well as predictions that human-induced climate change would bring a greater chance of hotter weather in the UK summer.

Meteorological summer ends on 31 August. This is because meteorologists split the year into four even quarters, each made up of three months, for ease of record keeping and statistical analysis.

Long range forecasts are now looking ahead to meteorological autumn - the months of September, October and November.

As autumn marks the transition from the warmth of summer to the colder conditions of winter, this can be a trickier season to make broader predictions for.

There are however a few factors that could point to another warm spell in September.

Computer forecast models are suggesting that high pressure may become established to the south of the UK through the first part of September.

High pressure leads to dry and mostly sunny weather at this time of year.

It may also draw up some warmth from continental Europe, boosting temperatures and the possibility of a hotter spell.

July was the driest on record across England and Wales with more than two thirds of England and all of Wales currently in drought.

When soil is very dry, air temperature can rise more rapidly that it does when soil is wetter. This is because no energy is lost in evaporating any soil moisture so it goes directly into heating the air.

While there is rain this week, it will not be enough to fully saturate the soil and make a difference to the drought situation.

Marine heat can also influence the temperature on land. The seas around England and Wales are currently up to 3C above average.

This extra warmth from the sea can also keep the temperature higher on land.

All the factors above can load the dice for hotter spells to affect the UK.

The long-range forecast for September, October and November from the Met Office suggests that the chance of a warm three-monthly period is "higher than normal".

They go on to say that this will bring an "increased risk of heatwaves and heat-related impacts, especially during the first half of the period".

With September still two weeks away, we can not yet suggest when - or indeed if - this will happen. We can only say that the risk is there.

The long-range forecast also suggests that the three-monthly period of autumn is likely to be drier than average.

With the Environment Agency suggesting we need "weeks of above average rainfall" to alleviate the drought situation, there is no sign of any major improvements in the immediate future.

You can keep up to date with the latest longer-range forecast with our monthly outlook.