The Met Office forecasts Wednesday as the warmest day of the week across parts of the UK, with temperatures possibly reaching 20C in western Wales and western England.

Chief forecaster Dan Harris stated that east to south-easterly winds passing over higher ground will cause this rise through the Foehn effect. The phenomenon happens when moist air rises over mountains, cools and produces precipitation on one side, then descends and warms on the other.

Northern Ireland will experience mostly cloudy conditions with occasional light rain on Wednesday, according to BBC Weather. Conditions remain mild.

The current highest temperature of the year stands at 19.2C, recorded in London on March 5. High pressure will dominate, leading to clear skies in some areas and chilly nights with possible air frost.

Sunshine develops in southern and western UK areas today, with some spots reaching 17C. Temperatures stay above seasonal averages on Thursday before returning to normal on Friday.