SPORTS SCIENCE

When it comes to baseball, sweaty balls make for long balls

When it comes to baseball, sweaty balls make for long balls
Minute Maid Park was built with a retractable roof for a reason. Ronald Martinez/Getty Images

Recently I stumbled across an article highlighting how executives from an anonymous MLB team reached out to NOAA’s National Centers for Environmental Information to request weather data for all of the cities in which they play.  Given the importance that has been placed on analytics in this era of sports, it should come as no surprise that teams are looking to factors beyond the playing field and thinking outside of the box in attempts to gain any possible advantage.  

This un-named team (but let's be honest, there’s a very good chance it is the Astros) did not disclose exactly how they would be using the data, but based on the information requested it is safe to assume the team is looking at factors beyond just wind and rain.  More than likely these club executives are also taking account of temperature and humidity conditions at each ballpark. Both of these factors share one commonality which affects the flight of a baseball off the bat and out of a pitcher's hand - air density. On a very basic level air density is a measure of how many air molecules are present in a given area.  

As the temperature warms air molecules begin to move faster causing the air to expand. This expansion leads to more space in between the molecules which in turn lowers air density.  Humid air is also less dense, even though most people describe the air as feeling heavy when it is muggy out. The lower density is due to the fact that water molecules are actually smaller than the nitrogen and oxygen molecules that make up the majority of the air we breathe.  When the air is more saturated (humid) water molecules displace more of those larger molecules creating a less dense air mass (Nerd moment – this is the same reason humid air rises to create storms).

Knowing what kind of temperatures and humidity levels to expect at certain stadiums can help teams make tweaks to their hitting and pitching strategy.  In cooler or drier conditions the air is more dense which can lead to a little more movement on breaking pitches due to increased friction, while in hot and humid weather, or at high altitude like in Denver, the air is less dense giving fly balls a bit more oomph towards the fences.

In Houston we have an abundance of heat and humidity for 99% of baseball season which is part of the reason Minute Maid was built with the retractable roof.  Although the overall effect of air density is rather small - when combined with the Astros’ ball-mashing lineup and short outfield corners, the heat and humidity are assets not to be discounted for the home team. So on those hot and muggy summer nights perhaps the Astros should open up the juice box and let the dingers fly.   

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The Astros beat the Royals, 7-3. Photo by Ed Zurga/Getty Images.

Yordan Alvarez’s long home run backed a solid start by Hunter Brown as the Houston Astros beat the Kansas City Royals 7-3 on Sunday in the series finale to avoid being swept.

Alvarez snapped Houston’s 26-inning scoreless streak, crushing Kris Bubic’s sinker 436 feet to center for a three-run homer and a 3-0 Astros lead in the third inning.

Brown (4-1), who allowed one run on seven hits and a walk with nine strikeouts over six innings, surrendered a lone hit in each of the first four innings but struck out seven while not allowing a runner past second.

Brown’s 28-inning shutout streak – fifth longest in franchise history – ended in the fifth inning on a two-out single by Jonathan India and an RBI double by Bobby Witt Jr.

Leading off the fifth, Chas McCormick doubled and scored on Jeremy Peña’s single. McCormick had three hits and scored three runs for the Astros.

Peña’s two-out, two-run double in the sixth extended Houston’s lead to 6-1. Peña collected three RBIs in his first game batting leadoff.

Yainer Diaz added a solo home run in the seventh.

Bubic (2-2) allowed four runs on five hits and three walks, striking out four in five innings.

India had a pair of singles and drove in a run while Witt extended his hitting streak to a career-best 19 games.

Key moment

Isaac Paredes drew a four-pitch walk ahead of Alvarez’s three-run blast.

Key stat

Alvarez, who led left-handed major leaguers with a .362 average against left-handed pitchers in 2024, hit his first homer of this season against a left-hander.

Up next

The Astros open a three-game homestand Monday against Detroit with Tigers RHP Jack Flaherty (1-2, 2.63 ERA) opposing RHP Ronel Blanco (2-2, 5.01).

Tuesday, the Royals begin a three-game series against the Rays in Tampa with Royals RHP Michael Lorenzen (2-3, 3.90) against RHP Taj Bradley (2-1, 5.08).

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