It was messy. It was melancholy. Just like the entire Raiders farewell.

It was loud. It was a party. Just like the Raiders’ stay in Oakland.

As the fans gathered late Monday afternoon, at the Coliseum, for what may or may not be the final game in Oakland for the Raiders, the weather was dreadful. The people, and the parking lot, were shrouded in funereal black.

The diehards chose to spend their Christmas Eve on the corner of the 880 freeway and 66th Avenue with a team that already has abandoned them. For their trouble, they were treated to wretched weather conditions before the game.

But nobody seemed to mind. This was an event. A wake. A farewell.

The Raiders won 27-14 against a disinterested Denver team. Although it was a nice parting gift for the fans, the victory also underscored just how few wins the Raiders have given their fans in recent years.

As the game neared its end, security guards and police ringed the field. A loud “Let’s go, Raiders” chant broke out. Fans were dancing in the stands and eventually on top of the dugout.

And when the final seconds ticked off, some Raiders — including quarterback Derek Carr and head coach Jon Gruden — ran to the Black Hole to give high-fives. Carr did an entire circuit of the stadium, reminiscent of Steve Young’s post-NFC Championship Game victory route at Candlestick Park in January 1995.

But that was for a championship win. This was merely a farewell. Before the game, the fans were drenched by a downpour. A vicious wind whipped their Raiders hats off their heads and sent their Raiders tents cartwheeling across the parking lot. The bourbon got diluted with rainwater, the silver and black face paint ran down faces, and the signs of farewell got soggy.

“It’s a little melancholy, a little sad,” said Andy Coronado, who drives his Raiders bus, decorated in Raiders memorabilia, to every game from his home in Stockton. He has been a fan since the last time the Raiders left Oakland and he had a wet flag flying above his bus that said, “thx 4 da memories.” He and his daughter had waterproofed smaller signs to bring into the game.

“It’s not his first rodeo,” a friend cracked.

Nor was it his first goodbye.

The parking lot was full of many of the previously rejected. The ones wearing Stabler jerseys and Branch jerseys and remembering what the Coliseum was like before Mount Davis was built and before people dressed up in Halloween costumes to come to the games. The ones who said goodbye once before.

Back on Dec. 13, 1981 — just like on Monday — no one knew for sure if it was the last game. The concerns were more with how ineffective Marc Wilson was at quarterback and how lousy the Raiders, just one season removed from winning Super Bowl XV, were playing. Back then, teams didn’t pick up and move and they certainly didn’t abandon the best fans in football, so most people ignored Al Davis’ legal machinations.

It wasn’t until the next May, when a jury ruled in favor of Davis, that the Raiders’ move to Los Angeles became a reality.

Unlike that move, this one has been the endless goodbye. A parting of prolonged torture. The stadium is being built in Las Vegas. The move is a reality. What’s not known — because of the factions involved — is if there will be one more season in Oakland. Or somewhere else in the Bay Area. Or somewhere else entirely. Over the weekend, playing a full home schedule in London was floated by NFL insiders.

In contrast to the previous generation of the abandoned, the current fans had a choice to make: Stick with the team post-breakup or not? Many did this year, because of the promise Gruden’s arrival brought.

But now many of those same fans feel they were taken, suckered into believing there could be some success while still in Oakland. Those hopes vanished before this woeful season even started as the dismantling of the team began before a game was played. Khalil Mack and Amari Cooper will both be playing football in January while the Raiders will be scrambling for a place to park their rebuilding product.

Another face no longer in uniform, Marshawn Lynch, lit the Al Davis memorial torch. It was a symbolic nod to Oakland. Lynch, who is on injured reserve, is Oakland born and raised. But it felt a little like pandering: Hey Oakland, you’re really, really important to the Raiders. Look, we trotted out the most loyal Oaklander we could find, despite our disloyalty.

Loyalty has its limits. Wherever the Raiders play next year, a significant portion of fans will have decided that enough is enough. That there’s no reason to keep on investing in this team.

But some will sign up again. Will follow the team no matter where it goes. Will shout “Raaaaaaiders” to anyone who will listen.

The tailgaters lingered in the parking lot long past the game’s start and the party continued in the decrepit, sodden stadium. The football has become secondary to the social side. After all, the dreadful product the Raiders have put forth for almost all of the 24 seasons since they’ve been back in Oakland isn’t exactly a uniter. But the friendships, the grilled sausages, the cold beer, the ritual of Sundays, has kept them going, even through the bad times. Even through the downpours.

“We’ll stay to the end,” Coronado said. He meant the end of the game, despite the damp, chilling weather. But he also meant the end of this run. And maybe even to Las Vegas.

Outside his bus, his friend played “The Autumn Wind” on a trumpet. The autumn wind had turned into a biting winter blast. A signal of the end.

Ann Killion is a San Francisco Chronicle columnist. Email: akillion@sfchronicle.com Twitter: @annkillion