Warm, dry weather on Tuesday will fade and turn cloudy in south-western areas tonight with outbreaks of heavy, thundery rain heading northwards through Wednesday, according to the Met Office.
Bleak conditions are expected to last through to Saturday with "very unsettled" weather next weekend, risk of gales, and possibly even hail.
"Temperatures will mainly be on the cold side of average," said the Met Office.
Those hoping for another weekend heatwave any time soon may be disappointed, according to the forecast.
"Thereafter, for the remainder of April and into early May, unsettled conditions are likely to dominate, with a chance of showers or longer spells of rain and some periods of stronger winds, especially in the west and southwest," it said.
The disappointing forecast comes after people across the UK basked in soaring temperatures during an unusually hot Easter weekend.
— Met Office (@metoffice)April 22, 2019
All four UK nations recorded their hottest ever Easter Monday, the Met Office said, while Wales, Scotland and Northern Ireland also recorded their highest-ever temperatures for Easter Sunday.
The scorching temperatures were down to a period of high pressure, according to meteorologists, helped by the fact that Easter fell later in the calendar than usual this year.