 And with possible rain in the forecast for the 4th, the Sioux Falls Fireworks Show may be postponed. Organizers say the show would be moved to Friday if rain and thunderstorms persist on Thursday. About 10,000 people are expected to attend the show at the WH Line Fairgrounds this year. As of now, gates are set to open Thursday at 7 p.m. with the fireworks show at 10 p.m. The event is free along with free parking.