Front lawns, car interiors, patio furniture—these are just three of the many items directly affected by summertime weather factors such as temperature, air pressure, humidity, and wind. Baseballs are another, which is why representatives of an undisclosed Major League Baseball team recently contacted NOAA’s National Centers for Environmental Information (NCEI) for information on the weather conditions at every major league baseball stadium.
Insights of NCEI’s Integrated Surface Database
Obviously, NOAA doesn’t have weather stations inside each of America’s major league ballparks, so to comply with the team’s request, NCEI dug into its Global Surface Hourly (GSH) database, which compiles global hourly observations from a variety of sources, including more than 20,000 weather stations. In doing so, the GSH database can provide meteorological data on a variety of factors -- precipitation, temperature, dew point, winds, visibility, cloud cover, barometric pressure – for a given location at a specific time.
A Common Practice?
Just what this un-named Major League Baseball team is doing with this information from the GSH database is unclear—the team chose not to reveal its strategy citing the competitive nature of its business. However, given the influence that meteorological factors can have on a baseball in flight, it is probably safe to assume that the team is to trying to gain a competitive edge by anticipating the typical weather conditions for a given park at a specific time of day. As one sports-betting website put it, “ There are many different variables in play when trying to [predict the outcome of] a baseball game. One of the biggest that gets overlooked is the weather.”
Weather and the Physics of Airborne Baseballs
So how do meteorological conditions affect baseball games? Well, beyond rain delays and games cancelled due to severe weather, the right combination of altitude/air pressure, humidity, temperature, and wind can conspire to turn a fly ball into a home run, or vice-versa.
- Altitude/Pressure – The higher you are in the atmosphere the thinner the air, meaning there are fewer air molecules present and less air pressure. This means a baseball moving through the air of a high-altitude park will experience less resistance than a ball traveling through the air of a ballpark built at sea-level (sorry Florida Marlins). Now you know why Coors Field in the “mile-high” area of Denver, Colorado, is known as a “hitters” park.
- Humidity – Like an increase in altitude, humid air masses are less dense than drier air mass because there is more space between molecules. Again, a baseball traveling through air of decreased density will go farther than one traveling through air of increased density.
- Temperature – As air warms it expands, which makes warm air less dense than cold air. Warm temperatures therefore can help a ball travel farther. In fact, it’s been said that warmer-than-average temperatures across the country may have played a significant role in the home run spike of April 2006.
- Wind – More obvious than the effects of humidity and pressure, perhaps, is the impact that wind can have on a baseball’s speed and the distance. Wind that hits a baseball head-on will slow it down (think friction), but winds blowing in the same direction as an airborne ball can carry it further. The prevailing wind direction is often a consideration when designing and building a ballpark.
Of course, baseballs aren’t the only part of the game affected by the weather. The players have to contend with the elements too, particularly if they’re taking the field in an open-air stadium. High temperatures and high humidity can have a direct impact on a player’s performance, and this has prompted training staffs throughout the league to make sure their players are well hydrated. Doing so not only keep players from getting fatigued, it can help prevent injury. As a trainer for the Texas Rangers noted in a recent article from The Atlantic, players on his team frequently experience more “soft-tissue injuries” during the warmer months (e.g., August and September), which the team attributes to “excessive heat and fatigue.”
Although it’s not clear just how many Major League Baseball teams are incorporating weather data into their game-day strategies, this is the first time a professional team has contacted NCEI. However, with the Earth’s global surface temperature on the increase and questions about how this trend might affect the amount of water vapor (i.e., humidity) in the air, NCEI may soon get a whole lot busier.