Extreme heat is an ongoing hazard for outdoor sports. In response, schools, recreation departments, and fitness clubs are increasingly installing shade pavilions over venues like football fields and tennis courts. While shading is known to improve thermal comfort and reduce heat stress, its effects on wet bulb globe temperature (WBGT) and related activity modification guidelines in sports remain underexplored. This study uses a modeling approach to quantify the impact of shade pavilions on WBGT and activity modification across a range of U.S. climates. WBGT values were calculated using a model based on historical data from 221 weather stations, each with more than 30,000 hourly observations. Three environmental conditions were analyzed: full sun, shade, and shade combined with mechanical ventilation. The shaded scenarios were designed to represent the lowest possible WBGT values under ideal conditions. Activity modification thresholds were determined using the American College of Sports Medicine (ACSM) WBGT guidelines. Shading alone reduced midday WBGT by an average of 2.4 °C, with an additional reduction of 1.4 °C when mechanical ventilation was added. These cooling effects were largest during peak solar radiation hours, especially in the western and southeastern United States. The benefits of shade varied by region. Hotter areas like Phoenix and Miami saw the greatest increase in days where normal activity could occur, with up to 67–68 additional days per summer, compared to minimal changes in cooler cities like San Diego. Further field research is needed to validate these modeled results across different climates, sports, and shelter designs.
Grundstein et al. (2026) studied this question.