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Posted at 10:40 AM ET, 10/02/2008

Weather and Baseball

Wx and the City

Now that baseball playoffs are underway, let's talk about weather and baseball. Not just whether a game is cancelled due to weather, but how weather affects the ball itself. The best atmospheric recipe for a farther hit? High altitude, low pressure, high humidity, high temperatures and winds blowing out of a stadium.

How do each of these elements help the flight of a baseball?

Keep reading for the answers. And see our full forecast through the weekend.


Altitude can influence a baseball's flight in a big way. The higher up in the atmosphere, the lower the air pressure and the fewer the air molecules. So baseballs travel with less air resistance -- aka drag or frictional force -- in higher altitudes (there's a great graphic here that shows this concept). Given the location of Nationals Park, the Nats have very little elevation to help them out.

In addition, if a low-pressure system is approaching the stadium, the drop in pressure will also cause the ball to go farther. In fact, if air resistance weren't a factor at all, the ball could travel twice as far.

Also, the movement of air around a curved surface and the difference in air pressure this causes are what make a curveball possible.


High humidity actually yields air that is less dense, thus providing less air resistance for a traveling ball and allowing it to go further. This is an interesting and counterintuitive fact due to water vapor being lighter (in mass) than oxygen and nitrogen in air. Taking it back to high school chemistry, density equals mass over volume. The more water vapor that's present in the air, the lighter and less resistant the air is. Check it out.


Air expands as it warms. So warm air is less dense -- there's more space between the air molecules -- than cold air. Warm temperatures therefore also help a ball to travel a bit farther. Warmer-than-average temperatures across the country may have played a significant role in the home run spike of April 2006.


Wind also has an obvious effect on a baseball's speed. Winds that meet a traveling baseball head-on will slow the ball due to increased friction. But, winds blowing in the same direction as the ball can help carry it farther. Wind affects both batted and thrown balls. Even the speed and path of a pitcher's fastball can be slightly altered by the wind. The prevailing wind direction is often a consideration when designing and building a ballpark.

In a game of inches, the potential for weather to impact the outcome of a game can't be discounted.

By  |  10:40 AM ET, 10/02/2008

Categories:  Wx and the City, Wx and the City

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