The PGA Championship is the lone major that allows its players to practice in shorts.
With the August summer temperatures making for steamy practice rounds at Bellerive Country Club, it was a welcomed bonus.
Here's a look at some of the PGA's finest players who rocked the shorts best.
McIlroy joined Tommy Fleetwood and Sergio Garcia at the iconic Gateway Arch of St. Louis for a Closest to the Hole challenge at Monday's practice round. Rory is looking to take home his third Wanamaker Trophy, having won two in three years between 2012 and 2014.
Jordan Spieth, Billy Horschel
One is looking for a career grand slam. Both are looking for their first Wanamaker Trophy. Spieth and Horschel size things up at Monday's practice round from Bellerive.
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Garcia was enjoying his Tuesday on the links despite unfriendly weather triggering a delay. He's come close to winning the Wanamaker twice, his last T-2 coming in 2008.
The 2017 Rookie of the Year is appearing in his second PGA Championship, looking to become one of the youngest players to ever win a Wanamaker Trophy.
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Collar popped, shorts engaged. The man who answers to "Kuuuch" is still chasing his elusive first major. He had his best finish in 2015 when he finished T-7 at Whistling Straits.
Cool, calm and collected. Hossler is all smiles Monday as he prepares for his first PGA Championship.
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The 23-year-old is making his third PGA Championship appearance, also looking to become one of the youngest to ever win one. Here he tees off on a gloomy, weather-suspended Tuesday from Bellerive.
Hadley, who had his best finish at the PGA Championship in 2015, launches one at the driving range at Monday's practice round.
Rory McIlroy, Kevin Streelman, Phil Mickelson
McIlroy (left), Streelman (center) and Mickelson (right) all rocked the shorts on their Tuesday walkthrough of Bellerive with an unidentified man who also enjoyed wearing shorts. There are three combined championships in the group, with McIlroy notching two (2012 and 14) and Mickelson one (2005), leaving Streelman looking for his first Wanamaker.
Fresh off his first major, the 2018 Open Championship, Molinari looks fresh escaping the bunker at Bellerive on Tuesday.
Hoffman, who is still looking for his first major, rears back to escape the sand during Tuesday's practice round.
DeChambeau, who made his PGA Championship debut last year with a T-33 finish, has some fun at the Long Drive Competition.