The days are getting shorter, and colder in the northern hemisphere. Some worry about the ice and snow that is likely to come. But for many sports fans in the United States, this is ideal football weather. American professional football has developed a large base of diehard fans in the U.S. Now, it is trying to expand to include a worldwide audience. VOA's Ernest Leong has more.

Most professional football teams in the U.S. are part of the National Football League

Football games have become special occasions in the United States. Most of the professional games in the National Football League [NFL] are played on Sundays from September until late January.

Millions of fans around the country pack into stadiums and local bars to root for their favorite team. Some fans meet hours before the game in the stadium parking lot for an event called a "tailgate party," where they barbecue food and serve drinks, while discussing the upcoming game.

Longtime Washington Redskins fans Buddy Wedsel and Brian Philips talked about some of their tailgate party rituals.

Wedsel: "Like I said, we have theme food here. So we're playing the [Philadelphia] Eagles today, so we're having cheese steaks and hoagies [which are popular in Philadelphia]."

Philips: "It's just a time for, basically, extended families to get together and come out -- share some camaraderie before the game starts."

Robert Losey is an Associate Professor of Finance at American University, and an avid Redskins fan. He explains the game's reach in the U.S. culture. "So it's very popular. It's on TV. It's on the local news. It's on radio. It's everywhere you look at it."

Losey says one reason for football's popularity is the varied body types and skill sets each player brings to the game. "There's the 300 pound [136 kilogram] guards, that are massive and strong as oxen. And then there's the 180 pound [80 kilogram] wide receivers that are fleet [quick]," he said.

Redskins' defensive player Anthony Montgomery says the violence of football is also an important factor in the game's popularity. "I think people like the violence of it, really. I mean, you know, it's violent, and it's legal, and guys are out there hitting each other."

American football is based on the games of rugby and soccer, both popular sports in many parts of the world. Like rugby, points are scored by carrying or catching a ball and crossing a line in the opponent's territory.

Another way to score is to kick a ball at a goal.

Like most sports, the ultimate goal of all professional teams is to win the top prize in a final match. In rugby and soccer, it is the World Cup. In the NFL, it is the Super Bowl.

Two NFL teams, the New York Giants and Miami Dolphins, played an official game in Britain recently. While it was unusual for some to hear both the American and British national anthems sung at an NFL game. The game, played in a packed stadium in London, looked and sounded like any other football game played in the U.S.

Redskins' receiver Antwaan Randle El says it is American football's similarities to popular sports like rugby and soccer that could appeal to fans in other countries. "In certain countries, they play soccer, and they call it football. But they want to know [what] this other thing we [Americans] call football's about," he said.

Redskins' teammate and quarterback Jason Campbell says he enjoys playing football because of the teamwork and cooperation. "You know, that's why we enjoy playing it a lot. It's not an individual sport, you know, a lot of people have to come together. And it teaches you about life. And it teaches you about how to come together as a team."

On this Sunday, the Eagles were the better team. They came from behind to beat the Redskins.

Elation for the Eagles. Disappointment for the Redskins.

Throughout the league, similar scenarios are played out. For those who lost this Sunday, there is always next Sunday, and another chance at redemption. And another reason for fans to return and cheer their team on.