An autumnal heatwave is heading to the UK this week – a shift in weather which will be welcomed by many following a pretty subdued summer for Brits.
But what does this mean for our weather overall – and for climate change?
Here’s what you need to know.
What’s happening with the weather this week?
The Met Office has forecast that temperatures may climb to 29C on Monday, possibly reaching 32C by midweek.
As the Met Office deputy chief meteorologist Chris Bulmer said on Friday: “Fine and settled conditions will develop and, along with this, we will see a rise in temperatures across most parts of the UK next week.”
He said that many locations may experience 25C or above, which brings the UK into heatwave territory.
The highest temperatures are probably going to be in the south and the east – but the country as a whole is still going to have a pretty sunny time in the next few days.
Crucially, Bulmer also said that “temperatures are likely to be the highest for many since June or July.”
Why does the term ‘Indian summer’ keep popping up?
“Indian summer” is a phrase to describe a warm, calm spell of weather seen in the autumn, “especially in October and November” according to the Met Office’s Meteorological Glossary, published in 1916.
The exact origin of the phrase is not very clear, though, as the Met Office’s website explained. It could stem back to the US, and may refer to the warm, hazy autumn conditions “that allowed Native American Indians to continue hunting”.
It was first recorded in a letter written by Frenchman John de Crevecoeur, from 1778, where he describes Mohawk country by saying: “Sometimes the rain is followed by an interval of calm and warm which is called the Indian summer.”
Is this autumnal warmth a sign the UK summer is shifting?
While climate change is changing our environment constantly, having a warm autumn is not new for the UK (or even Europe).
According to Collin’s Dictionary, that phrase refers back to St Martin’s feast-day, listed as October 31 in the pre-Gregorian calendar, although it’s now November 11. Collin’s also suggests this phrase originates from between 1585 and 1595.
And, as the Met Office explains, “there is no statistical evidence to suggest that such warm spells recur at any particular time each year – warm spells during the autumn months are not uncommon”.
This warm wave in autumn is part of the natural weather pattern, triggered by the jet stream (strong winds blowing from west to east).
What can this tell us about climate change?
Although this is not as alarming as other signs our world is warming up (such as the southern Europe heatwave seen in the summer), it does seem as though autumn is getting warmer.
The warmest recorded temperatures for autumn have all occurred in the last few years – the warmest UK October on record was on October 1, 2011, with 29.9C in Gravesend.
Ceredigion had the hottest November on record on November 1, 2015, with 22.4C.
Only last year, there was a “false autumn” across much of Europe, when temperatures soared beyond 20C.
Peter Stoll, climate change expert, told The Guardian last year the impact of the perfectly natural jet stream is “being exacerbated by climate change”.
And, as chief executive of the Royal Meteorological Society (RMS) Liz Bentley told the BBC in 2020, that “the basic climatology of each of the seasons is changing, has changed, and will continue to change.”
She said the UK will still have four seasons even amid the climate crisis, but they will become more extreme as our world warms up.
She said: “It just means each of the seasons are going to be different from what we would have had a century ago or 50 years ago, because the temperatures are going up and the rainfall patterns are changing.”