The sunshine figures for spring would even be extremely unusual for summer and only three summers would beat spring 2020 for sunshine hours.
May has been exceptionally dry and sunny with the month becoming the sunniest the UK has seen since records began, the Met Office said. The announcement has raised concern about climate breakdown.
England has seen its driest May on record and Wales its second driest in records stretching back to 1862, with just 17 percent of average rainfall for the month for both countries.
The UK has also experienced its sunniest spring in records stretching back to 1929, with 626 hours of bright sunshine - beating the previous high of 555 hours in 1948 by more than 70 hours.
And May 2020 has been the sunniest calendar month on record with 266 hours of sunshine, beating the previous record of 265 hours in June 1957, the Met Office said. Overall it has been the fifth driest spring for the UK and the eighth warmest.
It is a dramatic shift from the winter with its record wet February, and the Met Office said it is the largest difference in rainfall between a notably wet winter from December to February and a dry spring from March to May.
The dry, sunny weather and continuing coronavirus lockdown are now putting pressures on water demand, prompting industry body Water UK to urge gardeners to avoid using sprinklers in the evening - though the wet winter means there is no prospect of hosepipe bans in the future.
Guy Shrubsole, a Friends of the Earth's nature campaigner, said: “February feels like a distant memory for many reasons but it was the wettest one on record.
"The Environment Agency in England had almost 600 active flood warnings, a number that’s never been that high. Then May saw cracked and parched ground, crops wilting and rivers looking for all the world like they are in severe drought."
He added: “There was only 4mm of rain in the entire south east England for the month. It’s not good enough to just try and enjoy the dry weather when it’s actively harming crops and records are being broken with alarming frequency.
"Climate breakdown fuelled by carbon emissions can only mean more extreme swings, making us go from floods and droughts in a few months, with all of the misery that both cause.
“As lockdown lightens decision makers need to see both crises, climate and virus, as having the same solution: invest in a green and fair recovery.”
Dr Mark McCarthy, the head of the Met Office's National Climate Information Centre, said: "The most remarkable aspect is just how much some of the May and spring records for these climate statistics have been exceeded.
"Exceeding the UK sunshine record is one thing, but exceeding by over 70 hours is truly exceptional. The sunshine figures for spring would even be extremely unusual for summer and only three summers would beat spring 2020 for sunshine hours.
"The principal reason for the dry and sunny weather is the extended period of high pressure which has been centred over or close to the UK."
In the exceptional conditions, water companies have seen a huge rise in demand for water from households, particularly in the evenings, with use up 20 percent and some areas seeing peak demand of up to 40 percent above normal for the time of year.
Along with cutting sprinkler use, steps to reduce water use include taking shorter showers, making sure the dishwasher is full and on an eco-setting before running it through, and reusing paddling pool water on the flowerbeds, Water UK said.
But the industry body stressed people should keep following the guidance on protecting their health during the pandemic, by making sure they wash their hands regularly.
And after the wet winter, there are good supplies of water in reservoirs and there are currently no plans for hosepipe bans in the UK, Water UK said.
Water UK chief executive Christine McGourty added: "These are exceptional times and the record-breaking dry weather is a powerful reminder of what a precious, natural resource our water is.
"With so many people at home and enjoying their gardens, water companies are seeing record demand for water, which can cause issues with water pressure.
"Working together, we can all make a difference right now, so let's use water wisely.
"We need to keep washing our hands, but make other small changes to our water use, for example cutting back on paddling pools and sprinklers, particularly at the peak times in the evening."
Sir James Bevan, chief executive of the Environment Agency, said that in the prolonged dry weather the message to customers was to use water wisely but not to stint on hygiene measures to tackle Covid-19.
He told the Public Accounts Committee: "At the moment, although this is putting a lot of pressure on the water companies, the water companies are managing.
"But they will only be able to continue to manage if everybody is responsible in how they use water over the next few months."
But in the committee hearing on water supply and demand, he also acknowledged that telling people to conserve water when utilities were losing so much in leaks was a problem.
"It does undermine the 'use water wisely' message, so it needs to be addressed," he told MPs.
Emily Beament is the PA environment correspondent. Brendan Montague is editor of The Ecologist.