Think the May heatwave is bad? Scientists have warned that the worst is yet to come.

Yesterday was the hottest May day ever, as temperatures in Kew Gardens, London, hit 34.8°C (94.6°F) – obliterating a record that has stood since WWII by a full 2°C (3.6°F).

However, this unprecedented heat is just the start of the UK's weather woes.

According to climate experts, human–caused climate change and a 'super El Niño' weather cycle are 'loading the dice' for even hotter conditions.

Professor Liz Bentley, Chief Executive of the Royal Meteorological Society, told the Daily Mail that summer will see 'widespread temperatures over 30°C'.

'It is difficult to predict exactly how hot it could get this summer at this point in May,' she said.

'However, we are seeing more frequent heatwave events [due to] climate changes, and these heatwaves are becoming more persistent and more intense.

'It is likely that we will see temperatures exceeding 30°C on numerous days over the summer, and quite likely we could see temperatures rising above 35°C.'

Over the bank holiday weekend, three separate, long–standing temperature records were shattered by an enormous margin.

Not only was it the hottest May day, with the previous record set at 32.8°C (91°F) in 1944, but it was also the hottest bank holiday Monday and the hottest May night.

On Sunday, those living in Kenley, Greater London, cooked in overnight temperatures of 21.3°C (70.3°F).

This made it the UK's first ever 'tropical night' in May, which is a night in which temperatures do not fall below 20°C (68°F).

For comparison, Monday's record heat already equalled the hottest temperature recorded in 2024 and exceeded the hottest temperature in 2023.

According to climate experts, these unusually hot temperatures have been triggered by a combination of short–term weather patterns and the background of the warming climate.

While climate change doesn't strictly cause heatwaves to occur, it is making them more frequent and more intense when they do emerge.

That means the UK is being battered by stronger heat waves that last longer, reach higher maximum temperatures, and come around more often.

A study conducted by the Met Office last year found that breaking the 1944 temperature record had become three times more likely due to human–caused climate change.

Compared to a climate unaltered by human action, extreme heat that would have been a one–in–100–year fluke is now a one–in–33–year event. 

Professor Ed Hawkins, of the National Centre for Atmospheric Science and the University of Reading, told the Daily Mail: 'Today’s heat events are emerging earlier, intensifying faster, and occurring across a much warmer background climate.

'Burning fossil fuels has made this heatwave hotter – this is true for the UK today, and everywhere else, all of the time.'

Since heatwaves are strongly shaped by short–term atmospheric patterns, scientists don't know yet just how bad they could get this summer.

However, the data suggests that the odds are now stacked towards a brutally hot summer.

Professor Hannah Cloke, of the University of Reading, told the Daily Mail: 'While no one can say exactly how hot the UK will get this summer, the background conditions are certainly loading the dice towards unusual warmth.

'Scientists are increasingly confident that climate change is making extreme heat in the UK more likely, more intense and more prolonged, even though the exact timing and severity of individual heatwaves cannot yet be predicted months in advance.

'If persistent high pressure develops over western Europe during the summer, that warmer background climate can allow temperatures to build more easily and remain elevated for longer.'

The chances of a hot summer are particularly high this year, given the background of the global climate.

Global temperatures currently remain 'exceptionally high' following years of record–breaking heat, and scientists now say a new El Niño event is on its way.

This is part of a natural cycle known as the El Niño–Southern Oscillation, a natural climate pattern which cycles between a hot El Niño and a cool La Niña phase every two to seven years.

During the El Niño part of the cycle, warm waters that build up in the Pacific spread out and raise the Earth's average surface temperature.

Currently, global warming is being held in check by a cooling La Niña pattern that is making 2026 a little bit less hot than previous years.

Now, unusually hot sea surface temperatures indicate that the return of strong or 'super' El Niño conditions is likely as early as May or June.

Some scientists have even suggested that we could be approaching the strongest El Niño cycle in the last 140 years, with the potential to send global temperatures soaring.

A recent study, led by Dr James Jansen of Columbia University, predicted that this has a very strong chance of making 2026 the hottest year ever recorded.

Combined with the heating effects of human–caused climate change, the researchers predict this year's super El Niño will make 2026 0.06°C (0.11°F) hotter than 2024.

'El Niño does not directly cause UK heatwaves,' says Professor Cloke.

'But it can influence large–scale atmospheric patterns around the world and may increase the likelihood of warmer global conditions overall.'

Scientists expect the biggest impacts of El Niño to be felt at the end of 2026 and into 2027, but these changing patterns could push the British summer over into record–breaking territory.

However, there is still a chance of a cool summer and this week's intense heat doesn't necessarily mean the rest of the year will be record–breaking.

Stephen Dixon, Met Office spokesperson, told the Daily Mail: 'While the recent warm weather has been provisionally record–breaking for May, this doesn’t impact the likely conditions through summer as a whole. 

'Just small changes in the weather can lead to significantly different conditions through summer. So while we can say that we obviously expect further warm weather at points during the summer, it’s not possible to say exactly where or when.'