Soaring temperatures mean some parts of the UK will be as warm as Ibiza, Barcelona and Madrid on Tuesday.
The UK could be set to record one of its warmest days of the year so far, with areas of the South East predicted to hit highs of 17C, according to the Met Office.
Such temperatures would be 8C warmer than the average 10.3C for that area at this time of year, and potentially match Spanish hotspots.
The warmest areas are expected to be in the south of England.
Temperatures will have to pip 18.3C, however, recorded on February 20 in Northolt, north-west London, and Kew Gardens, south-west London, to become the hottest day of 2017.
The average maximum temperature for this time of year, taking in all of the UK, is 8.9C - significantly lower than highs reached on Monday.
Murlough in County Down enjoyed 15.9C, the Giant's Causeway hit 15.8C, while St James's Park in central London reached 15.3C.
Towards the end of the week temperatures are predicted to fall, but remain just above the average maximum highs for mid-March.
The highest-ever UK-recorded temperature in March was in Mepal, Cambridgeshire, 1968, where it reached 25.6C.