Temperatures are likely to reach up to 25C by the weekend, 10C higher than the average for May, according to forecasters.
The whole of the UK and Ireland is expected to experience a steady increase in temperatures this week. Scotland and Ireland are likely to hit up to 19C while the South-east should have the hottest weather. Temperatures are due to return to the May average of 15C next week.
Aisling Creevey, a MeteoGroup forecaster, said: "For the rest of the week it's looking warm with temperatures well into the 20s. At the moment the winds have changed direction, south-westerly, and the origin of the air is warmer. But next week is likely to move back to the average for May, which is about 15C to 16C in southern parts."
There will be a little rainfall, with mist and fog also predicted in western and northern parts. Temperatures have been several degrees below average in recent weeks because of cool north-westerly winds, plunging as low as minus 6C in Altnaharra in the Scottish Highlands last week. Skiers and snowboarders are still enjoying snow on Cairngorm Mountain.
Independent forecaster Positive Weather Solutions (PWS), which accurately predicted last year's wet summer, has forecast "warm to very warm" temperatures for June and July, but with rain in mid-June and early July, and with "pleasant" weather continuing into August.
Jonathan Powell, of PWS, said: "The pattern through June is unlikely to be all that stable, so expect some rain as we pass through mid-month, although there will be some pleasant sunshine from time to time."Reuse content