Weather experts have said a "dark cloud" will hang over Britain as mourners gather to say their final farewell to Queen Elizabeth II.
But there is a chance the sun will break through the clouds at Buckingham Palace where tens of thousands are expected to flood the streets for her funeral in London on Monday.
The monarch died peacefully, aged 96, on Thursday September 8, at her beloved Scottish estate Balmoral.
King Charles III declared the date as a national Bank Holiday to allow Brits to pay their respects.
The funeral day will start off with bright spells of sunshine in the morning, but as the service gets underway in the afternoon the skies will turn cloudy, the Met Office predicts.
Weather expert Simon Partridge said at the very least, everybody should remain dry, with the chance of the sun breaking through the clouds at Buckingham Palace.
"Being outside, it will be pretty decent conditions. It won’t be too hot or too cold and the main thing is everybody should stay dry as well," he told the Mirror.
"There will be some cloud around but with some bright, sunny spells at times.
"It might be a touch cooler than the average for this time of year, so we are looking at 18 or 19 degrees.
"That's not cold by any stretch but not as warm as you would expect for early September."
Light winds, patch clouds and sunny spells are on the cards for Londoners on the day of the royal funeral, and the forecast may improve nearer the time.
"There is a chance of seeing some sunshine at times," the Met Office weather expert added.
"It is quite a way off but nearer the time, it may turn out that there is a little less cloud than the models are showing at the moment."
The Queen's state funeral will begin at 11am on September 19 at Westminster Abbey following a procession of her coffin from Westminster Hall.
Many heads of state, key dignitaries and other public figures are expected to be invited for the service which will be led by Very Reverend Dr. David Hoyle, the Dean of Westminster Abbey.
The Queen's coffin will be lowered into the Royal Vault before being interred in the King George VI memorial chapel, located inside St George's Chapel.
It is expected to cause huge travel disruption with several major roads closed off, and will be the largest security operation the UK have ever seen.
