Britain could be set for an Indian Summer this week. The Met Office says a jet stream is continuing to shift north, allowing higher pressure to build widely across the UK. The jet stream has been bringing largely unsettled spells of weather to the UK but that is all set to change, as temperatures could reach 29C on Monday and get as high as 32C by midweek.

On Friday, Met Office Deputy Chief Meteorologist, Chris Bulmer, said: “Fine and settled conditions will develop and along with this we will see a rise in temperature across most parts of the UK next week”.

The second reason for the heatwave is said to be due to the influence of former tropical cyclone Franklin, continuing to move into the North Atlantic, causing high pressure.

“Many places can expect to see maximum temperatures rise to 25C or above for several days, which would bring some locations into the realm of heatwave conditions,” Chris Bulmer added.

“Although the highest temperatures are likely to be in the south and east of England, these areas also have higher temperature thresholds for heatwave conditions to be declared.

“So, while some areas may just miss out on the actual definition, regardless of thresholds, many areas will enjoy a fine period of weather with plenty of sunshine and temperatures are likely to be the highest for many since June or early July.”

What is an Indian Summer?

An Indian summer describes a warm, calm spell of weather that occurs during autumn.

Why is it called an Indian Summer?

In the Met Office’s Meteorological Glossary, published in 1916, an Indian summer is defined as “a warm, calm spell of weather occurring in autumn, especially in October and November.”

There are different theories about the exact origins of the phrase. Some say it may originally have referred to a spell of warm, hazy autumn conditions that allowed Native American Indians to continue hunting.

It was first used in the eastern United States, in a letter written by a Frenchman called John de Crevecoeur dated 17 January 1778. In his description of the Mohawk nation, he writes: “Sometimes, the rain is followed by an interval of calm and warm which is called the Indian summer.”

In the UK however, the term “Indian summer” was first used in the early 19th century and went on to increase in popularity. Previously, the phrase “Saint Martin’s summer” was widely used across Europe to describe warm weather surrounding St Martin’s Day (11 November).