Weather is a significant factor used to determine whether an MLB game will stay under the total or go over. However, many people betting on Major League Baseball games often misunderstand the impact of weather.
You can take the example of how the direction of the blowing wind at Wrigley Field can result in a Home Run Derby or how people assume thin air in Coors Field will get two more runs per night.
Let’s discuss how you can take weather into account when betting on MLB totals.
Forces Affecting a Flying Baseball
Before understanding how the weather impacts a hit or thrown baseball, we need to first look at the physical forces impacting the baseball when it’s in the air. The two primary forces that affect a flying ball are gravity and friction.
Gravity pulls the ball in the downward direction and friction is dependent on factors such as air temperature, humidity and pressure. These factors together change the density of the air. When the air is less dense, fewer air molecules are present to exert a drag force on the baseball, resulting in the ball flying a greater distance through the air.
Hence, if the weather factors including temperature, pressure and humidity remain constant, a baseball will go further when the air is less dense.
For example, Coors Field is mile high and has less dense air so the ball will travel 9% further compared to the denser air of Yankee Stadium, which is built at Sea level. This means a baseball shot of 400-foot at Yankee Stadium would go 436-feet in Coors Field.
Impact on Thrown Balls
Apart from deep fly balls, air density also affects the thrown balls and the fielders running after the ball. So if a pitcher throws a fastball, it will travel further in less dense air and reach the plate faster. But if he throws a curveball, a slider, a splitter or cutter, they won’t retain the same break. This is because less dense air at mile high level will contain less friction and the ball will curve less.
Hence, a pitcher throwing a baseball on higher elevation will have more curve, with some studies noting a difference of up to 3 inches.
Similarly, outfielders also suffer from less dense air where the baseball gets quickly into the gaps, and they need to cover more ground in less time. For example, at seal-level, the range difference is 9 feet for outfielders while for mile-high parks, the range difference is one foot for infielders.
The Effect of Wind
The wind has a drastic effect on flying balls and can turn a flying ball into a home run, or on the contrary, knock a home run into a long out.
The wind can also change the trajectory of baseballs and push them further left or right depending on the wind’s direction. If a strong wind is blowing in, the balls are affected by a greater drag force and stay in the yard, while winds blowing out help the ball travel further outfield.