Behind the Forecast: How weather impacts soccer matches

LOUISVILLE, Ky. (WAVE) - Whether watching or playing, the weather can considerably impact the sport of soccer.

First, let’s focus on temperature. Warmer air is lighter than cold air. On warmer days, a soccer ball may travel further due to reduced drag compared to a chilly day. The altitude at which the game is played could also have an impact. At higher altitudes, the thinner air provides less resistance and allows the ball to travel farther.

Temperature and pressure are directly related. As the temperature rises, so does the pressure inside the ball. On hotter days, the ball can become slightly over-inflated; the opposite is true on a colder day.

Of course, the wind can blow a soccer ball off course. It can cause them to move unpredictably and make freekicks hard to manage. Strong winds can force teams to change their strategies in games.

Rain and thunderstorms are not ideal. Muddy and slick turf can lead to less foot and ball traction.

Lynn Family Stadium, home of Louisville City and Racing Louisville, has specific protocols for severe weather.

• In the event of severe weather in the vicinity of Lynn Family Stadium, fans should listen for public address announcements, keep an eye on the video board, and follow the club on social media to receive any pertinent updates.
• Should fans be advised to exit the stadium for shelter due to conditions, re-entry will be allowed once the game is scheduled to resume.
• Upon a resumption of play, games will restart from where they stopped, preceded by a warmup period. If a game is postponed to a later date, tickets and parking passes from the original date will be honored.
• Generally, soccer games go on through rain unless conditions make playing impractical or dangerous.
• Regular-season NWSL games can be declared official after the first half is complete.
• Regular-season USL Championship games can be declared official after 70 minutes are complete.

Hot and dry weather isn’t great for players either. To protect players from heat stroke and heat exhaustion, hydration breaks have become mandatory midway through halves during the summer. Racing Louisville’s Vice President of Communications Jonathan Lintner explained that “There’s an obvious player safety element to it, but the idea is also that if players get a moment, the stoppage will result in a better and more energetic overall game. Plus the time (about three minutes) gets added on to the end of the half anyway.”

Referees use a wet bulb thermometer before kickoff to determine the temperature. If the temperature is hotter than 82°, then there will be a hydration break for players. The WetBulb Globe Temperature (WBGT) is a measure of the heat stress in direct sunlight, which takes into account: temperature, humidity, wind speed, sun angle, and cloud cover (solar radiation). The WBGT is different from the heat index, which takes into consideration temperature and humidity but is only calculated for shady areas.

Measurements are taken at the center circle with special devices.

For the NWSL, games can be delayed if the temperature is higher than 95°; games resume once the temperature cools down.

Lynn Family Stadium has a sub-air system, according to Lintner. It removes soil moisture to prevent puddling and helps maintain growth conditions (it also provides heat to prevent the grass from freezing in the winter.)

Many Racing Louisville and Louisville City players prefer a wet field without rain. When the sprinklers run before games and during halftime, allows the ball to move faster over the surface.

• Racing Louisville FC’s Gemma Bonner
  • On her favorite weather for a match: “Cloudy, with a wet field for sure. No rain. Not too hot, but I like the surface wet so the game’s quicker – the ball moves.”
  • On playing during the summer: “I hate the hydration breaks. You need them, but for players, we get a three-minute break, but then there’s like seven minutes of injury time, so you still play them.”
• Louisville City FC’s Josh Wynder
  • On his favorite weather for a match: “I like 70-degree weather – probably a little cloudy so the sun’s not beaming down on you. It’s OK if it rains before the game, but preferably not during the game.
  • On playing during the summer: “You have to hydrate as much as you can, and then any chance you can during a game.”

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