Britons will be mistaken to think it’s summer this week, as swathes of UK towns see sweltering temperatures up to a sizzling 20C. Thursday’s the first day of astronomical spring, or the ‘spring equinox,’ and after a snow, blizzard, and rain-battered 2025, forecasters predict a huge turnaround in temperature after a chilly start to the week.
And BBC Weather experts suggest the peak of the heat will be Thursday when the mercury is expected to reach seven or eight degrees warmer than the normal average. London, West and South Wales, and central England, will roast the most – while in the north of the UK, temperatures are expected to reach 11C (51.8F) in Edinburgh and 14C (57.2F) in Belfast.
And if the 20C London forecast holds, Thursday will be the hottest day of 2025 – with the warmest so far being 9th March, when Crosby in Merseyside, reached 19.7C (67.5F).
Met Office meteorologist Becky Mitchell said: “The spring equinox will coincide with some nice warm weather, definitely feeling spring-like.”
Tuesday this week looks to see any early patchy cloud and mist clear to leave a dry and fine day with plenty of sunshine. Staying cloudier in Northern Ireland with breezes in the south and west.
Wednesday will continue dry and bright for most and it will turn even milder with sunshine after any early patches of mist and fog clear.
But Thursday 20th March looks set to be the brightest and hottest, as the mercury rockets to 20C (68F); while Swindon, Peterborough, Birmingham – and in Wales, Cardiff and Caernarfon – hit 19C (66.2F).
Meanwhile five major towns and cities will be a toasty 18C (64.4F) – Southampton, Newtown, Manchester, Lincoln and Kendal – and another five enjoying a cosy 17C (62.6F); Norwich, York, Pembroke, Plymouth and Brighton.
WHERE WILL IT SIZZLE ON THURSDAY?
20C
London
19C
Swindon, Wiltshire
Peterborough, Cambridgeshire
Caernarfon, North Wales
Cardiff, South Wales
Birmingham, West Midlands
18C
Southampton, Hampshire
Newtown, Powys
Manchester
Lincoln, Lincolnshire
Kendal, Cumbria
17C
Norwich, Norfolk
York, North Yorkshire
Pembroke, south west Wales
Plymouth, Devon
Brighton, East Sussex