Becuase Universal is right in the middle of a neighborhood, they have to really limit when they can do fireworks becuase people complain.
Fireworks will be going on from July 4th until the middle of August. After that, nothing has been said. It is likely that the last week of Dec. they will do them leading to the big display on New Years becuase the last week of Dec. is a NIGHTMARE for crowds.
Even when they do the show, not a ton of fireworks are used. It is more of a show with lasers than major fireworks. A lot of the show will just have you watching the globes in the water. I really wish they would change the show to feature more fireworks since they are so limited. I also wish they would have another version of the show without any fireworks during the whole year. It sucks not having anything to see before the park closes.