While we often focus on the rules changes that have helped make passing offenses much more efficient over the years, there’s another small reason for the improvement in aerial attacks: better climates. Let’s compare the stadiums in the NFL now to the stadiums of the early 1970s.

Expansion/Re-Location

There are 7 new cities (and one deserted city) that have joined the NFL since the early ’70s, when the league still had just 26 teams.  Five of these new cities helped the passing game by bringing in more mild-climate games due to warm weather locations or indoor stadiums. ^[1]Note that I am ignoring the California changes here. The Rams played in southern California in the ’70s and now, even if there was a St. Louis stop in the middle (which that was mostly indoors, … Continue reading

• There was no team in Indianapolis, which has an indoor stadium. ^[2]Of course, the Colts played in Baltimore, and no longer do; but for purposes of looking at geography, there was a team in Baltimore in the ’70s and a team in Baltimore now; Indianapolis is the … Continue reading
• The Cardinals did not play in Arizona, which has an indoor stadium, but instead played outdoors in the 1970s in St. Louis (the deserted city).
• There was no team in Tampa Bay, a warm-weather city
• There was no team in Carolina, a warm-weather city
• There was no team in Jacksonville, a warm-weather city

While those fives changes made passing easier by decreasing the impact of the elements in the northern cities, two changes increased the impact of the weather.

• There was a team in Houston playing indoors at the Astrodome, but the franchise founded by Bud Adams now play outdoors in Nashville, Tennessee. Of course, they were replaced by another team playing inside in Houston.
• There was no team in Seattle, which is a cold-weather city.

Moving Inside

Five teams moved from outdoors to indoors from 1970 to 2019:

• Detroit played outdoors at Tiger Stadium until 1974.  They now play indoors.
• New Orleans played outdoors at Tulane Stadium until 1974.  They now play indoors.
• Minnesota played outdoors at the old Metropolitan Stadium until 1981.  They now play indoors.
• Atlanta played outdoors Atlanta-Fulton County Stadium until 1991.  The Falcons then moved indoors.
• Dallas played outdoors at the Cotton Bowl until 1971 and then the open-roof Texas Stadium until 2008; that still provided for some bad-weather games.  The Cowboys now play at AT&T Stadium, which is a retractable roof stadium that is usually closed.

Northeastern Changes (3)

In addition, there’s the Jets and Giants, who used to play games at old Giants Stadium (well, the Jets were at Shea Stadium in the ’70s, also a poor stadium for passers; just check out the home/road splits for Joe Namath).  Giants Stadium was also a legendary bowl of swirling winds, but the new MetLife Stadium has much softer effects.  And the Patriots have seen a similar change: while the temperature has remained the same (average of 51 degrees) the average wind at old Foxboro Stadium was about 14 miles per hour; at Gillette Stadium, it’s down to 8.5 miles per hour for the average game.

No Changes — On The Surface (17)

Seventeen cities haven’t seen any massive change in terms of weather: teams in Cincinnati, Chicago, Baltimore, Green Bay, Washington, Kansas City, Denver, Pittsburgh, San Francisco, Philadelphia, Buffalo, Miami, and Cleveland played outdoors in the early ’70s and do so now. There was a dome team in Houston in the ’70s and a team playing inside in Houston now. The Rams were in Los Angeles at the beginning of the ’70s and end of the ’10s, so we count them here, too.  The Chargers moved from San Diego to Los Angeles, and the Raiders have bounced around, but those changes have been mild (and the team will now play in a domed stadium in Las Vegas).

That said, there have been some subtle changes that involve more complicated explanations. Temperatures are getting more mild; the most notable example is in Cincinnati, where the Bengals played at Cinergy/Riverfront Stadium from 1970 to 1999; the average temperature was 50.0 degrees and the average wind was 10 mph during those games. The Bengals have played at Paul Brown Stadium for the last 20 years, and the average temperature has been 54.6 degrees with a wind of 8.4 miles per hour.

Summary

There has been only one move over the last 50 years that increased the impact of weather on NFL games: the addition of Seattle (And, it should be noted, the Seahawks began by playing inside in the Kingdome) as an NFL city.

Seventeen teams/cities saw no material change; an 18th team brought Nashville into the NFL, but that is a warm-weather city that is about average in terms of NFL climate.

That leaves 13 teams that made life easier for passers.  The Jets, Giants, and Patriots moved into more friendly outdoor stadiums.  More dramatically, four teams (Atlanta, Minnesota, Detroit, New Orleans) moved inside, while a fifth (Dallas) moved inside most of the time.  And five other teams relocated to either indoor cities (Indianapolis, Arizona) or warm-weather cities (Carolina, Jacksonville, Arizona).

So when we think about how different the games looks now compared to at the start of the Super Bowl era, we should also remember that it feels a lot different, too: at least for the players.