Baseball stadiums are making changes to combat the weather so they can keep their attendance numbers up.
Currently, six of the 30 MLB stadiums have retractable roofs to counter uncooperative weather: Rogers Centre, home of the Toronto Blue Jays; Chase Field, home of the Arizona Diamondbacks; Safeco Field, home of the Seattle Mariners; Miller Park, home of the Milwaukee Brewers; Minute Maid Park, home of the Houston Astros; and Marlins Park, home of the Miami Marlins. A seventh park, Tropicana Field, home of the Tampa Bay Rays, has a fixed roof. The rest are open.
Closed roof at Marlins Park. Photo courtesy of verndogs
The six retractable-roof stadiums have varying reasons for needing the option to cover their field and their fans. Houston and Miami face issues with humidity, heat and rain. Houston's rainiest month is June, averaging nearly 7 inches of precipitation.
"Rain is a big factor for Houston, but a bigger factor for Miami," said AccuWeather.com Senior Meteorologist Dale Mohler. "It rains almost every other day there in the summer."
Miami averages over 9 inches of rain in June and has high temperatures in the 80s from April to October. Since high humidity often combines to make it feel even hotter, it can be very uncomfortable for fans.
With Houston sitting right on the Gulf of Mexico, higher humidity affects the city much more than stadiums located in the Desert Southwest. The Phoenix stadium, for example, doesn't have the same issues with rain or humidity, but it can relate in terms of heat. Summertime highs in Phoenix top the 100-degree mark for almost all of June to September. Even night games can have intense heat during the first pitch.
For Toronto and Milwaukee, it's the cold that causes most problems. Milwaukee averages low temperatures just above freezing when baseball season starts. Toronto is even closer to the freezing mark in April, averaging a low of 33 F. It's also not impossible for snow to interrupt games; the very first Blue Jays game was played in snow in 1977. Twelve years later, Rogers Centre became the first baseball stadium to have a retractable roof.
Seattle has fairly consistent temperatures, averaging in the upper 60s to mid-70s for the duration of baseball season. Though drier in the summer (July, the driest month, averages less than an inch of precipitation), they built a roof to protect the fans from rain.
The Miami Marlins are the most recent team to make the change to a retractable roof. Until the 2012 season, the team played as the Florida Marlins at the Sun Life Stadium, home of the Miami Dolphins. With their new state-of-the-art stadium they revamped their name, logos and uniform.
The Marlins came in 29th place in terms of attendance in 2013. So far this season, the Marlins have risen to 26th, as icy temperatures in Chicago and Cleveland have helped keep those teams' numbers down.
The Marlins have been using their stadium roof to respond to the weather and draw in crowds by providing more comfortable conditions for fans. They even use social media to help spread the word to their fans when they will be closing the roof.
Roof & Operable Wall will be CLOSED for tonight's rubber match against the Nats. #LetsGoFish— Marlins Park (@MarlinsPark) April 16, 2014
The varying presence of retractable roofs at these stadiums has also impacted ticket prices, according to research from secondary market search engine SeatGeek. In the cases of Miami and Houston, ticket prices are highest in the early months of the season, when better weather means it is more likely for the roof to stay open. Prices in Miami and Houston tend to decline as the season and hot, rainy summer months drag on -- and in recent years, as the Marlins and Astros have fallen out of contention in their divisions.
In Seattle, however, weather and time of year do not seem to have too much impact on ticket prices, as demand for Mariners tickets tends to be as consistent month to month.
Similarly, ticket prices to a game in Arizona generally stay flat or trend slightly downward over the course of the summer, with hot weather almost always compelling the Diamondbacks to keep the lid on Chase Field closed.
Prices in both of the cold weather cities with retractable roof stadiums show some signs of increased demand in summer months, when it is most likely that their roof will be open.
Although prices in Toronto tend to stay relatively flat month to month, the highest ticket prices of any summer month are those for games in July, when it is most likely the Rogers Centre roof will be open on game day. Demand for tickets to see a game in Milwaukee tend to rise over the course May through August, corresponding with the mild Wisconsin summer.
While it's less likely that some of the more historic parks will update their stadiums to react to the weather, the ways of the retractable roof may become more prevalent in the years to come as teams strive to fight off rain delays, bitter cold and blazing heat to keep the games going and the crowds in the stands.