The sound of cheering crowds and thunderous applause from the Marin Catholic stadium emanates far and wide in all directions, and is especially amplified in the Greenbrae “bowl” area, where the hillside creates an amphitheatre effect.
The reason sound often propagates more efficiently at night is that since sound travels faster in warm air than in cold air, the wave front becomes bent. The bending of a wave front between boundaries is called refraction. Refraction changes the direction of travel of a wave front. Consider for example that on calm, clear nights the air near the Earth’s surface is cooler than the air further above the surface. Air at rooftop height above the surface might be 1 or 2 degrees warmer under such ideal conditions. Sound will travel faster in the higher, warmer air than it will in the lower, cooler air close to the surface. A wave front will therefore become bent, or refracted, toward the ground on a cool night and you will be able to hear sounds from further away than on warm night.
Since most of the night games are scheduled for the late fall and winter months, it will almost always be cool, and sound will be much more likely to travel farther than on a warm night.