Play ball! How rising temperatures are powering more home runs

As the baseball season gets underway, one interesting weather factor affecting the game is warming temperatures. While fans may often focus on the players performance, the environment itself is quietly playing a bigger role than ever before.

Game-time temperatures have been steadily rising over the past several decades and it’s showing a correlation between the increase in temperatures and the number of homeruns hit.

Why is that?

The answer lies in a basic principle of physics: aerodynamic drag. When a batter makes contact, the ball has to fight against the air as it travels. Cooler air is denser, which creates more resistance on the baseball. Warmer air is less dense, which allows the ball to encounter less resistance.

Even a small increase in temperature can add a few extra feet to a hit. And in baseball, a few feet can mean the difference between an out and a home run.

Baseball season is heating up

Since 1970, average temperatures during the Major League Baseball (MLB) season have warmed by 2.8 on average across the 27 MLB cities. These top 10 MLB cities have experienced average temperature increases ranging from 3 to 5 degrees.

A recent analysis of Minnesota Twins home games shows that average temperatures during the baseball season have risen by more than 3 degrees since 1970. While individual seasons fluctuate, the long-term trend is unmistakable: baseball is being played in steadily warmer conditions.

A 2023 study found that rising temperatures, by lowering air density, have led to a measurable, though modest, increase in home runs across Major League Baseball. The full article from the American Meteorological Society can be found here.

The data is clear: warming temperatures are reducing air density, allowing balls to travel farther and nudging the game toward more home runs.

Baseball has always been a game of inches—but now, it’s also a game of degrees.