Why is the weather so bad? Met Office September forecast 'uncertain' thanks to hurricanes Idalia and Franklin

It’s fair to say that, overall, the weather has been lousy in the UK this summer. We’ve had a few warm spells, but on the whole it’s been rainy and pretty miserable. In fact, July was one of the wettest on record for the UK, according to the Met Office.

It won’t surprise anybody to know that, especially parents, carers and school pupils. That’s because there seems to be an unwritten, and rather unfortunate, rule that as soon as the schools break up for summer the weather will turn bad. There’s then another opposite unwritten rule at the end of the holiday; that it will turn good just in time for back to school.

But will the later weather tradition continue for 2023? The Met Office has given its prediction as we prepare for not only the beginning of a new school year but also the end of meteorological summer. Their verdict is maybe, and it’s all down to what happens with two Atlantic hurricanes, hurricane Idalia and hurricane Franklin. So, what exactly has the Met Office said? Here’s what you need to know.

What has the Met Office said about September weather?

On the one hand, the Met Office has said that we can expect the usual pattern of the weather settling down as soon as the schools go back to continue. But, in their latest deep drive forecast, Met Office meteorologist Aidan McGivern also said there could be a “spanner in the works” in the form of two hurricanes, and as a result the weather for September looks “uncertain”.

The first of these hurricanes is hurricane Idalia, which McGivern said it set to “rapidly intensify” over the course of today (Wednesday 30 August) as it moves towards the Gulf Coast of Florida. He added that it may become a “category three monster”, which means that it will have a sustained wind speed of 111mph and over. The hurricane has since been declared a categry four storm which means there may be "life threatening winds".

The second hurricane is hurricane Franklin, which McGivern described as a “very powerful system” but said it is “thankfully currently nowhere near land”. It is expected to join the mid-Atlantic, and that means it could affect UK weather by changing the shape of the jet stream and changing the position of high and low pressure.

McGivern said: “There are still things to play out and things are never certain when it comes to hurricanes and how they interact with the jet streams and affect our weather, but it looks likely that the warm air that circulates around areas of low pressure will push the jet stream well to the north.”

He added that there are then two ways that these hurricanes could impact UK weather. “Hurricanes can end up as ex-hurricanes and bring wind and rain to the UK, but [they could] just buckle the jet stream and push it out of the way of the UK. High pressure [would then] build in the UK, bringing plenty of fine weather.”

How long will the weather conditions last?

“It looks fairly likely that through the first week in September we’re more likely to see high pressure extending across the UK bringing plenty of fine weather. It means plenty of sunny spells, a lot of dry and fine weather [and] light winds.”

Early Met Office predictions show that the higher than normal pressure will continue across the UK during the second week in September, so we could be in for a mild start to the month and also therefore a mild start to autumn, if you follow meteorological autumn timings. There is, however, a possibility that southern areas may see a few showers developing, which at times could turn heavy and thundery as more humid air from the continent reaches these regions, according to the long-range Met Office forecast. 

Towards the latter half of the month, high pressure may shift further to the north or east, increasing the likelihood that eastern areas could see above-average rainfall, while western regions remain somewhat dry for the time of year. It may feel fairly warm for late September, with temperatures overall likely to be slightly higher than usual.

Will there be a heatwave in September?

There have been instances in the past where the UK has basked in unseasonably high temperatures during September - but McGivern has said that is unlikely to happen during the first half of September 2023. “This high pressure builds in a relatively cool air mass so we’re not expecting a heatwave by any means, but temperatures would probably end up just above average for the time of year.”

People in the south can expect temperatures around the mid 20s and people in the north can expect temperatures in the high teens or early 20s.