Today will be hot and humid, as highs will be in the lower 90s, and dewpoint temperatures will be in the mid to upper 70s. The humidity will make it feel like it is over 100 degrees. If you're at the speedway, stay hydrated and take frequent breaks in a shaded area.
Tomorrow should have slightly lower dewpoints, in the lower 70s, so it won't feel quite as muggy as today. Highs will be around 90, and winds will shift to the north at 5 to 10 mph.