Met Office meteorologist Jonathan Vautrey said there is a “lot of sunshine around to help to keep things feeling pretty warm” in the south of England, as temperatures reached about 23C in the Greater London area on Saturday afternoon.
But he added: “If we take a look further north-west though it is quite a different story, so western areas of Scotland and Northern Ireland are much cloudier today and we are actually seeing some very unseasonably strong winds, so we have seen gales across north-west Scotland, the Highlands and the Outer Hebrides and places like that with rain coming through as well, so temperatures here are struggling a bit more.
“It is the eastern side of Scotland that has sort of been pushing towards the high teens mark in terms of their temperature, just seeing a few more drier and and brighter spells.”
The Met Office had warned that ex-tropical Storm Alex would cause strong winds and showers, especially for western Scotland and Northern Ireland, on Friday and Saturday this week.
Mr Vautrey added: “We will sort of continue slightly with this north/west south/east split into next week as well, so we have high pressure building into the south which will allow things to stay relatively settled.
“At the moment, (it) doesn’t properly extend its influence across the entirety of the UK and that’s allowing low pressure and frontal systems to just fringe into north-west Scotland and Northern Ireland as well into the start of next week, so they can expect some spells of rain and showers at times.
“As we move into the end of the week, that’s when we are starting to pick up the signal for the potential for some significant heat to come up from the south.”
He said this was “still a fair way off at the moment”, so there is is still some uncertainty.
But Mr Vautrey added “there is a signal in that the heat we have currently got over Spain – I believe they are experiencing rather high temperatures at the moment – could edge its way northwards to south-eastern areas of the UK, at least for the end of the week.
“So at the moment, the model wants to take us up to mid-20s by the middle of the week and then potentially into low 30s for Friday, which would be the warmest conditions we have seen over the course of this year so far.”
The Met Office’s highest recorded temperature for the UK this year was 27.5C at Heathrow in Hillingdon, west London, on May 17.
England and the South East is set to enjoy the “hottest of the weather” because the high-pressure is not extending across the whole of the country, which will keep thing “cooler in northern areas”, but they “will probably still see a gradual increase in temperatures”, Mr Vautrey said.