The first day of spring could be the hottest of the year so far, as temperatures will rise over the next few days, the Met Office has said.
Temperatures of up to 21C could be recorded in London on Thursday, coinciding with the spring equinox.
Parts of the UK could be hotter than Barcelona in Spain and Athens in Greece, where highs of 15C and 12C are forecast respectively.
If temperatures do climb into the twenties, it could make Thursday the hottest day of the year so far for some – after a peak of 19.7C in Crosby, Merseyside, on March 9, according to the Met Office.
The temperature is expected to begin creeping up from Wednesday, with highs of 17C in London and the South East, a marked difference from the temperatures at the beginning of the week.
Warmer temperatures are also expected to come with dry and sunny weather for most of the UK.
Marco Petagna, a meteorologist at the Met Office, said: “Temperatures already just started to pick up in places, but the trend to warmer temperatures is going to continue for the next few days now.
“So Wednesday, lots of sunshine around parts of southern England and Wales.
“We’ll see some clouds developing, particularly towards the south west of England, but for most places, you have plenty of sunshine, and we’re drawing up warmer air now from the South and South East.”
The rest of the UK is more likely to see highs of 12C to 15C on Wednesday, Mr Petagna said.
He added: “And then for Thursday, probably the peak of the warmth, and a lot of fine weather around.
“Again, little bits of medium upper cloud around taking turns with the sunshine, a little bit hazy in places.
“But for most places, it will be a lovely day, a dry day with a good deal of sunshine.
“It’s going to be touch and go but potentially Thursday could be the warmest day of the year.”
After a cold and frosty start, Wednesday will soon warm up in the spring sunshine 📈🌤️
— Met Office (@metoffice) March 18, 2025
Perhaps turning a bit cloudier across England and Wales later with a few light showers possible in the southwest 🌦️ pic.twitter.com/mCRRCEmWgX
The sunny weather is expected to fade from Friday, with temperatures creeping down and some rainy weather over the weekend.
Mr Petagna said: “Temperatures are coming down from Friday onwards, and also some rain pushing in from the South and West.
“For the weekend, we’re looking at sort of 15C or 16C as a high on Saturday, and about 13C by Sunday.”
