ST. LOUIS—This week’s warm temperatures have already affected high school athletic events in the region, as the region remains under an excessive heat warning through Thursday evening.

Granite City High School confirmed that a girls varsity golf match scheduled for Tuesday was canceled, along with a Wednesday JV boys golf match against Alton Wednesday. In Collinsville, a varsity and JV girls tennis matches against Gibault scheduled for Tuesday has been rescheduled for Aug. 30. A girls varsity golf tournament at O'Fallon was cancelled.

Varsity and JV football practice has also been moved to 5:15 a.m. for Tuesday, Wednesday and Thursday.

What You Need To Know

  • The governing bodies for high school sports in Missouri and Illinois both use what’s known as the Wet Bulb Globe Thermometer (WBGT) to guide safety protocols

  • The WBGT measurement is different than the heat index because it weighs air temperature, humidity, wind speed, and sun angle or cloud cover

  • Each state has slightly different cut-off points that dictate specific protocols, leading up to the suspension of any outdoor activity. Check the protocols here: Missouri and  Illinois

  • Missouri rules say teams must have 14 conditioning practice days ahead of the start of competition

Illinois high school sports are already in the competition phase, while Missouri schools are still in practice mode leading up to Friday’s first scheduled day of competition, including a full slate of high school football games.

On Monday morning, Washington High School announced that Friday’s home football game against Union would move to an 8 p.m. kickoff as a way to beat the heat. Rockwood Summit move its kickoff against Webster Groves to 7:30 p.m. There will undoubtedly be others following suit.

The governing bodies for high school sports on both sides of the Mississippi River use what’s known as the Wet Bulb Globe Thermometer (WBGT) to guide safety protocols, although each state has slightly different cut-offs for making a particular decision.

According to the National Weather Service, Wet Bulb Globe Thermometers measure heat stress “in a particular place, and it combines air temperature, humidity, wind speed, and sun angle or cloud cover to give a comprehensive measure of the local environment.”

That’s a different measurement than the heat index, which looks at temperature and humidity and is often measured in a shaded area.

“We decided to cancel our home sporting events this afternoon after I took WBGT readings at 6:00 this morning. The WBGT reading I took at the tennis courts at 6am was already in the "yellow" zone of that chart, so I could tell that it wasn't going to be safe by 3:00pm,” Granite City Athletic Trainer Andrea Kovalsky told Spectrum News via email. The “yellow zone”, between 80-84.5 numerically in Illinois calls for at least three separate rest breaks an hour lasting five minutes each, and requires Cold Water Immersion therapy for heat stroke treatment to be available on site.

At noon, Kovalsky said readings taken on the school’s grass fields were already higher than 89.9, the point where no outdoor workouts or competition should take place.

In Missouri, the go, no-go line is at 92 for high school events and 90 for middle school. Events can move indoors if there is air conditioning available.

A spokesman for the Missouri State High School Activities Association warned a canceled practice could impact games scheduled for this weekend.

“Each participant must have at least 14 school conditioning practices completed prior to the first interscholastic contest. A canceled practice does not relieve any student of this requirement,” MSHSAA Communications Director Jason West told Spectrum News, meaning that schools without enough players who have reached the 14 day threshold could be forced to forfeit if conditions warrant.

A boys soccer jamboree at St. Charles West high school featuring several other area teams slated for Monday was canceled due to the conditions. One school, Parkway North, said it would have an indoor practice instead.