As springtime approaches, it’s time for baseball.

And that means it’s also time for the biggest humidors of all: baseball humidors!

Following the lead of the Colorado Rockies, which began using a humidor in 2002 (pictured right) to maintain uniformity in ball weight in the mile-high atmosphere of Denver’s Coors Field, all Major League teams are now required to:

• Maintain baseballs in storage at a constant temperature of 70 degrees and

• To only use baseballs manufactured for the current season.

By keeping baseballs at a constant temperature of 70 degrees and relative humidity of 50% – as recommended by the manufacturer (Rawlings) and not too far from the 70/70 level preferred for cigars – the Rockies found that the balls don’t dry out and become harder so that they fly faster and farther when hit.

The impact at Coors Field has been dramatic. In 1996, runs-per-game at the Rockies home park peaked at 15.0 runs per game! Since the introduction of the humidor in 2002, runs-per-game have dropped each year, reaching a low of 10.7 runs per game last season. The Denver Post noted that:

“By rule, a baseball can weigh from 5.0 to 5.25 ounces and measure from 9.0 to 9.25 inches in circumference.

“This is not an insignificant variance. MLB's own study at the University of Massachusetts-Lowell in 2000 found that a well-struck, 5.25-ounce, 9.25- inch ball could travel up to 49.1 feet less than a 5.0-ounce, 9.0- inch ball.”

Major League Baseball has not required humidity control along with temperature control, but it’s sure to come as teams try to create consistency in ball weight from game to game. The Rockies send in weekly reports on ball weight and it will only be a matter of time not just before all clubs are required to do so, but that Major League Baseball will send its own inspectors to make random checks on ball storage.