UK weather: 26C for parts of UK - but heavy rain warning for Scotland
PA MediaWhile much of the UK could see temperatures of up to 26C (79F) at the weekend, an amber weather warning for rain is in place in parts of Scotland.
The warning, which means a high risk of widespread disruption, is in place from 03:00 BST Saturday until 06:00 Sunday.
Police urged people to travel only if necessary in areas it covers.
A yellow "be aware" warning for heavy and persistent rain is also in place for almost all of mainland Scotland, as well as Skye and the Inner Hebrides.
The Met Office said parts of the Highlands and central Scotland, including Glasgow, Perth and Stirling could see up to 180mm (7in) of rain.
BBC Weather forecaster Matt Taylor said earlier there could even be snow over the highest Scottish mountains.
Highlighting "stark contrasts" in the UK's weather, he said: "While it will feel like late summer in the south, it will be more like late autumn/early winter for many in Scotland.
"Not only will there be persistent rain for many but temperatures will struggle to reach 10C for a fair few."
The period of heat for much of the UK is due to warm and humid air originating from north-west Africa and the Canaries, which has set many October records across Europe in recent days.
Over the weekend, a high of 26C is expected in south-east England on Saturday - this is unusual for October and even a little above typical mid-summer highs.
A temperature of 25C has only been reached or exceeded in three other years in the past quarter of a century - in 2018, 2011 and 2001.
However, the all-time October record of 29.9C, set on 1 October 2011 in Gravesend, is unlikely to be reached.
The heavy rain in Scotland could lead to some flooding, with up to 150mm (5.9in) falling over the hills, Mr Taylor warned.
The Met Office has predicted widespread disruption for the west coast, parts of the central belt and the Highlands including Glasgow, Stirling and Fort William.
It warned of potential difficult driving conditions, flooding for homes and businesses and danger to life from fast flowing or deep flood water.
In Northern Ireland, highs of 21C are expected, while Scotland will likely top out in the high teens.
Mr Taylor said warm conditions will likely persist into the early part of next week, with temperatures continuing to reach the low to mid 20s, before things turn cooler from the middle of next week.
"While the cooler conditions in Scotland this weekend may bring on the autumn colours, overall it looks like temperatures will largely be at or above normal in most areas," he explained.
"We could continue to see a split in fortunes rainfall-wise though. As low pressure systems dominate to the west and north-west of the UK, parts of western Scotland especially could continue to experience above-average rainfall."
Unseasonal warm weather is likely to become more common due to climate change, which is having an increasing impact on all parts of the UK.
It played a key role in pushing last year's temperatures to record highs.
The Met Office says 2022's record-breaking UK heat will be regarded as a cool year by the end of this century.