# Five Ways Weather is Pivotal in a Baseball Game

The impact of weather on a baseball game may not always be immediately recognizable as a heavy storm causing a rain-out, but it can be profound even on a bright, sunny day.

"The weather can impact every aspect of the game," said Mike Collins, head baseball coach at Bloomsburg University in Bloomsburg, Pennsylvania.

Baseball is a sport that is played throughout multiple seasons, so players must continuously adapt throughout the year. Below are five ways weather can affect the outcome of a game.

### Air Temperature Can Change a Baseball's Trajectory

Imagine watching a baseball game in the middle of April in colder weather and a batter launches a pitch deep towards the fence, only to have it fall into an outfielder's glove.

If the game is played during the summer months, you could see a ball struck similarly, only this time the outfielder positions himself to catch the ball only to drift farther and farther backwards as the ball carries farther than expected.

A fly ball out in April could be a home run in August.

"For a long fly ball, a ball hit with a sort of home run trajectory, that's a ball that's hit at about 100 mph off the bat, maybe at a 30-degree elevation angle," said Alan Nathan, professor emeritus of physics at the University of Illinois. "The numbers that I have found just by looking at the data, are that a 10 degree Fahrenheit change in temperature will change the distance by something like 2.5 feet."

"Now, that's not an enormous difference, if you're only looking at 10 degrees difference. But if you're looking at a difference between a 40-degree game in April versus a 90-degree day in the middle August, maybe the effects can be quite substantial."

### Air Density Can Play a Role in How Far a Ball Travels

Perhaps there's no better example in baseball than to examine the differences that weather conditions can have on the baseball at Coors Field in Denver, Colorado.

With an elevation of a mile above sea level, the ballpark already has an inherent trait that sets it apart from the 29 other Major League Baseball stadiums. Since it's at a higher elevation, the air density is lower. During the early years of the ballpark, it was evident that home runs were soaring over the fence at a much higher rate than the rest of the league.

Nathan said he has been studying the physics of baseball for the past 15 years and doing weather-related research since 2009.

According to an article he wrote for Baseball Prospectus in 2011, the Colorado Rockies began storing the baseballs in a humidor in 2002 at a constant 50 percent relative humidity and 70 F temperature to help change the coefficient of restitution, or simply, the bounciness of a baseball.

When the baseballs become heavier in the humidor, this reduces their bounciness and the ball doesn't come off the bat quite as fast, so therefore it won't travel as far.

In the first seven years the park was open, there were 3.20 home runs hit per game compared to 1.93 per Rockies away games. However, beginning from 2002-2010, after the introduction of the humidor, the home run ratio decreased to 2.39 while the away game total was 1.86 according to Nathan's article.

Certain weather conditions can have a similar effect on different styles of pitches thrown.

Curveballs and sliders, also known as breaking balls due to their spin and movement, will not typically break as much in less dense air, Nathan said.

Pitchers who are especially adept at these types of pitches can regain an advantage that may be lost in the summertime or even just when pitching at Coors Field.

"It would tend to favor pitchers who, when it's cold, the amount of movement will be greater than when it's warm so it would tend to favor those types of pitchers," Nathan said.

### Warm and Cold Temperatures Can Affect a Pitcher's Grip

Matt Jones, head baseball coach at Shippensburg University in Shippensburg, Pennsylvania, said there are occasionally some concerns with certain players, especially pitchers, when it's very hot and humid.

"Sometimes it's hard to grip the ball if you are sweating a lot," he said.

Jesse Leonard, head baseball coach at Juniata College in Huntingdon, Pennsylvania, echoed Jones' sentiments saying pitchers occasionally need to use a rosin bag to get a better grip when their hands are sweaty.

He added that cold air can affect a pitcher's grip as well.

"A lot of their pitches go on control and feel of the baseball, and if your fingers are slightly cold or slightly numb, it affects that grip and that feel."

Air temperature, density and humidity are just a few factors among many ways weather can affect the game.

### Cloud Coverage Can Affect How Players See the Ball

Whether it's a cloudy or sunny sky overhead can also have an impact. If there are cloudy skies, it can affect how an outfielder can see the ball off the bat.

Leonard said before games, he always goes over a "mini weather report" to discuss playing conditions such as which way the wind is blowing and if there are cloudy skies because that could affect the visibility for an outfielder.

Even a cloudless sky can pose problems, Leonard said.

"The â€˜high sky' that's bright and blue with no clouds, can be difficult when judging fly balls because of depth perception," Leonard said.

### Windy Conditions Have a Variable Effect on Players

The wind direction can have huge implications as well.

Collins said his team practices fly ball communication on every windy day, so game day can be the easiest day of the week.

He added that the weather impacts certain players differently. Some pitchers that rely on movement for their breaking pitches prefer to have some wind in their face.

"They feel like it will add to the movement on their pitches," he said. "Some are uncomfortable with it. It depends on the guy."

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