The Tartan Army seemed to have brought the famous Scottish weather with them as they arrived in their thousands.
However, the wet weather did little to dampen the spirits of the Scots and thousands arrived on sold-out trains and planes throughout the day.
Dozens of fans were filmed dancing and singing their adopted anthem Yes Sir, I Can Boogie, a 1977 hit by Baccara, outside the travel hub.
After Thursday’s scenes of fans dancing in a water fountain at Leicester Square and hosting an impromptu party at Hyde Park, the vibrant atmosphere continued on Friday morning.
The game gets underway at 8pm and the rain is not expected to let up until an hour or so before kick-off.
Scottish fans had been warned not to travel to London without a ticket for the match amid coronavirus restrictions.
While 2,500 Tartan Army supporters are expected as part of the 22,500 maximum crowd, it appears thousands more have made the trip south.
Scotland fan Michael McLean, from Inverness, told BBC Scotland he had decided to travel after booking travel and accommodation several months ago.
“It's an amazing atmosphere so far. I think it seems that they've underestimated how many would travel down for the game," he said.
“It's warm here and it feels like a normal football occasion. It doesn't feel like there's a pandemic on which I don't think is good in a way, but it's definitely good to enjoy an occasion after a year-and-a-half.”
Emma Best, a London Assembly member and the Conservative group's spokeswoman on health, said she estimated more than 20,000 Scotland fans would travel.
“The Tartan Army were everywhere - you'd be forgiven for thinking the game was today,” she told the BBC yesterday.
She added: “Like it or not, Scottish fans - and we must say English fans as well from across the country - will be in London in their thousands and so we do need a plan to manage that as carefully as possible.“