ALTON - The Marquette Catholic High School athletic department announced on Friday afternoon that it had canceled Saturday, Aug. 15, 2026, activities, and several schools also canceled Friday night, Aug. 14, 2026, football scrimmages in the St. Louis region. The National Weather Service in St. Louis forecast heat index values as high as 105 degrees on Friday afternoon and 106 degrees on Saturday afternoon.
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MCHS said it canceled all events due to extreme heat on Saturday, Aug. 15, 2026, including the Girls Blast Off Tournament at Spencer T. Olin Golf Course. Alton High's football team moved its scrimmage time back from 5 p.m. to around 7 p.m. on Friday.
The National Weather Service in St. Louis forecast a high near 95 degrees on Friday afternoon, with heat index values as high as 105. A 20 percent chance of showers and thunderstorms was expected before 3 p.m., with mostly sunny conditions and a south wind of 3 to 5 mph.
Saturday, Aug. 15, 2026, is expected to be mostly sunny and hot, with a high near 100 and heat index values as high as 106. The forecast calls for southwest winds of 3 to 6 mph.
The weather service lists excessive heat advisory criteria as a heat index expected to be around 105 degrees, or a heat index ranging from 100 to 104 for at least four consecutive days. Excessive heat warning criteria include a heat index expected to be around 110 degrees for two days, or around 105 degrees for four consecutive days.
The forecast calls for mostly clear skies Friday night, with a low around 78, and mostly clear conditions Saturday night, with a low around 77. Sunday is expected to be mostly sunny and hot, with a high near 97. A chance of showers and thunderstorms is forecast Sunday night, with a 50 percent chance of precipitation and a low around 73.
The National Weather Service in St. Louis briefing said young children, infants, older adults, people with chronic medical conditions, and pregnant women are among those at higher risk during extreme heat. It also said it is never safe to leave a child, disabled person, or pet locked in a car, even in winter, and that 31 children were reported to have died in hot cars in 2025.
The extended forecast calls for mostly sunny skies Monday with a high near 87, mostly sunny skies Tuesday with a high near 90, and mostly sunny skies Wednesday with a high near 95. A 30 percent chance of showers and thunderstorms is forecast Wednesday night, followed by a 30 percent chance of showers Thursday, when the high is expected to be near 85.
