How Milwaukee Brewers Decide When to Close Stadium’s Roof

Seven Major League Baseball teams have stadiums with retractable or moveable roofs. One of them is right here in Wisconsin.

American Family Field, formerly Miller Park, opened in 2001. The ballpark’s most distinctive feature is its moveable roof, which is made up of 12,000 tons of steel.

The fan-shaped roof has seven panels, five of which are movable. The roof, which is 200 feet above the field, “spans approximately 600 feet from home plate to the outfield track beam,” according to the Brewers website.

It takes around 10 minutes to open or close the structure, said Mike Brockman, the vice president of facilities and projects for the Brewers. During the course of a year, the club opens and closes it around 230 times.

The roof can’t be operated or moved when there’s more than 40 mph of wind speed outside or when the temperature falls below 20 degrees. It usually stays closed from December until the end of March, during the team’s offseason.

Is there a specific formula for when to open the roof?

Steve Ethier, the senior vice president of stadium operations for the team, said deciding whether the roof should be open or closed for a Brewers home game is an “art and a science.”

“The science (is) temperature, rain, winds. But then it’s … a little bit subjective, because you have a ‘feels like’ temperature and and also time of year,” Ethier said.

Brockman, Ethier and the head groundskeeper for the club are the main decisionmakers. They look at local forecasts, as they generally want the temperature to be 60 degrees or warmer during the course of the game.

“Then it really becomes rain or some inclement weather that would drive the decision whether to open or close … either during the course of the day or for the game itself,” Ethier said.

But it also depends on how it feels inside the ballpark. There were a few games earlier this season where the roof was closed even though the temperature outside of the stadium was above 60 degrees. Ethier said that’s because the temperature inside the ballpark felt colder.

The team tries to keep the roof open as much as possible during the summer because the stadium does not have air conditioning in the seating bowl.

However, the roof is more likely be closed for more games in the fall and during the postseason.

“Once we hit fall, we’re more likely to have the roof closed than we are in spring,” Ethier said.

How often is the roof open?

On average, the roof is open for 65 percent of the team’s 81 home games every season, according to Brockman. The earliest the roof was open during a season was Opening Day on April 5, 2010.

There have been at least two occasions the roof has been open when it started to rain during a game, including in 2019 that resulted in a short rain delay.

What happens when the Brewers decide to close the roof during a game?

The team will occasionally order the roof closed during the middle of a game. If there is a chance of rain or storms, Brockman will be in the control room on standby in case it needs closed. After the game starts, they need to get the permission of the umpiring crew chief in order to close the structure.

“Obviously, 24 years ago, it was more of a novelty than it is now. But it’s still, I think, entertaining for people to watch it,” Brockman said about the roof closing during a game.

The team can also keep the roof partially open for a game if they choose. That keeps more players and fans in the shade and blocks the sun if it’s a hot summer day.

The Brewers have a roof control room on the second level of the stadium. Fans can see it next to the entrance of the press box.

Brockman is one of a few people who actually presses the button that moves the structure. Before he pushes that button, he said he makes sure any contractors on the roof are aware of what’s about to happen.

Want to know if the roof is open or closed? Call the hotline.

Fans who are interested in finding out if the roof will be closed or open for a game just have to call the American Family Field Roof Hotline.

Brockman is the voice of that hotline. He said his neighbors recognized his voice when they called recently.

“Yep, that’s me,” Brockman said. “So every game day, I’ll update it and try to get it right. Sometimes we have a last-minute change of heart, and we’re open or closed, and the hotline is wrong.”

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How the Milwaukee Brewers decide when to open or close American Family Field’s roof was originally published by Wisconsin Public Radio.