Britain could be in for a hit-and-miss display of autumn colours, thanks to both the summer heatwave and the Super El Niño.

Experts are predicting those hoping for spectacular seasonal displays of fiery reds, deep browns and mellow yellows from maples, birches and oaks could be left disappointed, thanks to the 'false autumn' phenomenon.

The summer heatwave, which saw temperatures hovering in the late 30s - including 38.1°C recorded at Kew Gardens in August, has caused some deciduous trees to shed their leaves weeks early, meaning woodlands ablaze with colour might be less likely. 

The autumnal picture is also being influenced by the Super El Niño, which looks set to cause wetter weather in the coming weeks in the UK.  

The term El Niño describes the warming of sea surface temperature, a naturally occurring climate phenomenon that happens around every two to seven years and lasts for around a year.

Current temperatures recorded on the surface of the waters in the central-eastern Pacific have already exceeded those set during the strong El Niño of 2015.

Earlier this week, Dr Lucy Clarke, of Nottingham Trent University, told the Daily Mail that El Niño 'may increase the chances of milder, wetter and stormier weather, especially later in autumn and into early winter', adding: 'So it could lead to more unsettled weather during the coming months and may bring increased cold spells later in winter.'

After a brief spell of dreary weather, temperatures are climbing back to summer highs, with forecasts predicting 26C (79F) in London on Friday. 

Although the UK officially entered the autumnal period earlier this week, those heading out to leaf-peep are likely to find weather conditions have colluded against a stellar show this year.   

Speaking to the Daily Mail, Kevin Martin, Head of Tree Collections at the Royal Botanic Gardens, Kew, said: 'Following the UK’s hottest summer on record, we may not see the usual blaze of autumn colour arrive all at once this year. 

'Many trees across the country, particularly in the south, have already shed their leaves early in a phenomenon known as ‘false autumn’, which is a stress response to extreme heat and drought.'

This year's fall display is proving more complicated, added Mr Martin, but those seeking dramatic colours might still end up being pleasantly surprised.  

'At Kew, our 11,000 trees showcase species from around the world, and autumn normally brings a spectacular mix of scarlet red oaks, russet pin oaks and vibrant berries from viburnums and rowans. This year, however, the picture is more complex.

'False autumns are a warning sign. Trees can live for hundreds of years, but they are increasingly under pressure from a rapidly changing climate. 

'The good news is that recent rainfall could still bring a strong display from individual trees in October, and some species may put on an even more impressive show than usual.'

How colourful trees are in the autumn is an indicator of health generally, says Kew's Head of Tree Collections.  

'Trees are long-lived organisms, but they are under increasing pressure from a rapidly changing climate. And while autumn colour is beautiful, it also tells us something important about the health of our trees.'

Tomorrow, London and the South are expected to see temperatures ranging from 20C (68F) to 26C (79F), while Scotland and the North may see highs of 16C (61F).

However, the unusually hot weather for this time of year is only possible due to an exceptionally warm background.

Professor Hannah Cloke, a meteorologist at the University of Reading, told the Daily Mail: 'Right now there is high pressure sitting over us and drawing in warm air from the south. That gives sunny days in the mid–20s even this late in September.'

However, Professor Cloke warned that this 'sits on top of a much bigger picture' of human–caused climate change, which has shifted background temperatures.

'So when the weather pattern lines up for warmth, it gets warmer than it used to,' Professor Cloke added.

A recent rapid attribution study conducted by the Met Office found that this year's record–breaking summer was made 130 times more likely by climate change caused by burning fossil fuels.

Professor Friederike Otto, a climate scientist from Imperial College London, said: 'Following a record–breaking hot summer, we’re now into an unseasonably warm start to autumn.

'We know that every heatwave is made hotter and more likely by the emissions we’ve put into the atmosphere, primarily from the burning of fossil fuels.'

This unusual heat also comes against the background of a growing Super El Niño.

El Niño is part of a naturally occurring climate cycle called the El Niño Southern Oscillation.

This cycle alternates between a hot phase – El Niño – and a cool phase – La Niña – every two to seven years, with massive consequences for global weather.

During the El Niño phase, warm water builds up near the surface in the equatorial Pacific, driving up global temperatures.

The latest data shows the sea surface temperatures in this critical region are now 3.05C above the average for 1991–2020 – this has already overtaken the 3.02C record set in November 2015.

Scientists say it's now looking on track to be the largest in at least 1,000 years – with a possible peak of 4.1C in November and December.

Professor Cloke said: 'El Niño is now very strong and still growing. It is already shaping weather across the tropics: floods and drought in Central America, wildfire smoke across Southeast Asia, and a very quiet Atlantic hurricane season.

'But El Niño's biggest push on global temperature usually comes a few months after it peaks. So the real global heat boost is still ahead of us, into 2027.'

Experts anticipate that this will push up the average global temperature in the coming months and into next year, leading to above–average temperatures across all land areas this autumn.

According to scientists, this could lead to knock–on effects that may shape British weather throughout the autumn and into winter.

However, scientists insist that El Niño's direct impact on the UK's weather systems will be limited.

'El Niño has a strong grip on the Pacific and the tropics, but a weak and noisy one on our weather. Our autumn will still be driven mainly by the Atlantic and the jet stream,' said Professor Cloke.