Wimbledon is the only Grand Slam tennis tournament that’s still played on a grass court, and the only one that schedules a day off on the middle Sunday of the tournament. Wimbledon is also known for its rather rigid dress code. The rules specify that players must dress in white, and those rules are so strict that the referee can force players to change under threat of disqualification.
The rule stems from the 1800s, when tennis was a genteel sport played primarily at social gatherings, particularly by women. The sight of sweaty patches on coloured clothing was considered to be inappropriate, so the practice of wearing predominantly white clothing was adopted to avoid all the embarrassment. The All England Club, which hosts Wimbledon, was founded in 1868 and introduced Lawn Tennis in 1875, and the club is a stickler for tradition.
In fact, recently issued guidelines for clothing include statements such as “White does not include off-white or cream,” that colored trim can be “no wider than one centimeter,” and that “undergarments that either are, or can be visible during play (including due to perspiration)” are not allowed. That’s right: even players’ underwear has to be white.
Image source: https://www.theatlantic.com/entertainment/archive/