Highs of 20C (68F) are expected in parts of the UK this week, the Met Office has said, following a spell of cold, wet and windy weather.
Forecasters expect warmer weather to return mid-week, with southeast England set to enjoy the highest temperatures.
But there will still be scattered showers or longer spells of rain across the UK - and areas north of Newcastle, particularly the east coast of Scotland, will see the coldest temperatures this week.
Senior Met Office meteorologist Amy Bokota said:
"Temperatures have been below average for the last couple of weeks, so certainly by the time we get to Wednesday, and probably into next weekend, temperatures will be warmer.
"It might not be the sort of glorious sort of heatwave that we're hoping for... but there probably will be some more pleasant and warmer weather for some people as we head towards the end of the week."
The warmer weather comes after heavy rain interrupted sports matches and flood warnings were issued across the UK over the weekend.
Emergency services were called to assist two people inside a car that was submerged in around 50cm of floodwater under a railway bridge in Thurmaston, Leicester, on Sunday morning.
Cricket matches across the country were postponed or cancelled over the weekend because of the rain and soggy grounds, including Vitality County Championship games in County Durham, Yorkshire and Leicester.
The Environment Agency issued several flood warnings for Sunday, meaning flooding was expected, including in St Ives in Cornwall, areas on the River Wreake in Leicestershire, Water Eaton Brook at Water Eaton and several towns on the Isle of Wight.
So far this month, the maximum temperature recorded has been 21.8C in Writtle, Essex, on 13 April with a low of -6.3C recorded in Shap, Cumbria, on 26 April and a UK-wide average of 8.4C.
Grey skies and rain have made April feel unusually cold, the Met Office has said.
But it has actually been "on the warmer side of average", said Ms Bokota.
It has been a "been a month of two halves", she added:
"Quite warm for the first half, and then quite cool up until now."
It has definitely been "wetter than average for the UK as a whole", however, meaning many areas of the UK have been "quite dull so far for the time of year".
(c) Sky News 2024: Warmer weather is finally on its way, with parts of Britain set to bask in 20C heat
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