Britain could have its hottest day of the year on Saturday, with temperatures predicted to hit 26C (78.8F). Most of the country will bask in warm sunshine while London and the south-east will be hotter than Ibiza and St Tropez. But temperatures will plunge by as much as 15C (59F) on Sunday, as a cold weather front moves in from northern parts of Scotland. Saturday will be bright for most regions, hitting highs of up to 23C (73.4F) in northern England, 21C (69.8F) in Northern Ireland, 20C (68F) in southern parts of Scotland and 24C (75.2F) in Wales by the afternoon. London and the south-east could see the hottest temperatures recorded in the UK so far this year, potentially surpassing the 26C recorded in Treknow, Cornwall, on Good Friday. This has led the government to issue reminders to stay at home and obey physical distancing rules amid fears people could flock to parks and beaches for days out. There will be scattered showers across northern Scotland, with the chance of snow on the hills in the evening, with temperatures staying below 12C (53.6F) for the whole day. Met Office forecaster Craig Snell said: “Most of us will have some very warm and pleasant sunshine on Saturday, with London and the south-east possibly surpassing the 26C (78.8F) mark, which would make it the hottest day of the year so far. “This is because of southern winds coming in from Spain, which will make it warm and dry. “But this won’t be the case on Sunday; a cold front will move in from northern Scotland, meaning temperatures will plunge as much as 15C (59F) across the UK, with the possibility of snow in hilly areas. “These changes do sometimes occur in spring, as we’re in the middle of winter and summer, but this is quite a high drop.”