Mourners face a “less than 10% chance” of waiting in the rain to see the Queen’s coffin.
The Queen will lie in state for “four clear days” in Westminster Hall, arriving there in the afternoon of September 14, until 6.30am on the morning of her funeral, a senior palace official said.
The thousands expected to file past to see the late monarch’s coffin are likely to escape any rain amid warnings of long waits, forecasters say.
It came after officials in Scotland said weather conditions may be challenging with people warned to expect to stand for a number of hours.
Marco Petagna, a Met Office forecaster, told the PA news agency: “Tomorrow will be quite a cloudy day in Edinburgh with some patchy, light rain, however there’s every sign this will improve by the afternoon.
“Later in the day it should become a lot brighter with a reasonable amount of sunshine, temperature-wise staying fair at around 17C, despite a fresher north-westerly breeze, growing cooler overnight.
“Tuesday in the Scottish capital should be fine, with a fair amount of sunshine.
“Meanwhile, London should be fairly cloudy that day, yet rather warm at 22C, but the evening will be of some concern as thundery showers move in from the south.
“From Wednesday and until the funeral there will be a dry and fresher feel, with a fair amount of cloud and cooler winds and a less than 10% chance of rain.”
Further details of how the public can attend will be announced in the coming days.
Senior members of the royal family, including the King, will hold continuous vigils from 7.20pm on Monday known as the Vigil of Princes.