Rain is unlikely to fall during the Queen’s funeral with large crowds set to gather in London and Windsor.
The late monarch’s coffin will remain in Westminster Hall for the public to view until 6.30am on Monday, ahead of the service at Westminster Abbey.
Forecasters say temperatures will drop as low as 10C overnight into Sunday, as mourners continue queuing for the lying in state, before a warm and sunny day.
Temperatures had dropped as low as 4C for those waiting in line overnight on Friday and early on Saturday morning.
Rachel Ayers, of the Met Office, said: “Sunday is a cloudier picture across the UK than Saturday, though southern areas will see some bright or sunny spells to start.
“Scattered showers will affect the Midlands northwards at times throughout the day, particularly across northern Scotland and Norfolk where showers are feeding in from the North Sea.
“Staying cool in the east but temperatures near average elsewhere and locally feeling warm in any sunny spells in the far south.
“Top temperatures will be around 19C.”
During the one-minute national silence at 8pm on Sunday, the night before the state funeral, most of the country will avoid rain, with temperatures around 16C in the capital and Windsor.
Those in the queue for Westminster Hall will see a warmer night going into Monday, with lows of 13C, staying dry.
At 11am at Westminster Abbey, when the funeral takes place, the weather will be cloudy, with temperatures likely to hit 16C.
Conditions will stay the same when the Queen’s coffin makes the 1.5-mile journey from Westminster Abbey to Wellington Arch for the public procession at 12.15pm.
Some sunshine will break through the clouds in Windsor in Berkshire later in the day, with temperatures hitting 17C as the Queen is laid to rest.
Ms Ayers went on: “There may be some isolated mist and fog patches at first, most likely in the west.
“It will be cloudy in the far northwest with patchy rain at times, otherwise it will be another mainly dry day with sunny spells; though some cloud will bubble up later with a few isolated light showers in places.
“Light winds in general though it will be a breezy day in the far northwest.
“Chilly start, though by day temperatures will be near normal.”