Do catholics do exorcism only at night? For the past four nights, Catholics have been doing exorcism in one of the families in my neighborhood. They would start at about 10PM and usually end early the next morning, sometimes till 3AM sharp. They would even light crackers at these hours. Demonic possession is a very serious thing, but why would they do exorcism only at night? I don't think exorcism should be taken as something that you can take a break from until its done.
Having personally aided exorcists in various ways, I can assure you that not all exorcisms are performed at night. Neither does the Rituale Romanum of 1614 or the revised one in 1998, states when an exorcism is to be perform.  

That stated I will admit that many exorcism do occur at night. But this is more a question that those involved are entitled to their privacy. Most people are asleep at night and churches are thus empty and more available for priests to perform this Rite when possible (any other suitable dwelling may be used) in a more discreet atmosphere. A priest must never reveal the name of the possessed. This applies to those who assist the priest in their individual functions. 

The fire crackers that you are hearing is nothing more than the Devil or Demons involved making noise in order to impress those within ear shot and work on our imaginations. The Devil is a master of making illusions.

Exorcisms may take a priest a couple of times of performing an exorcism in order to liberate a person from the clutches of the demons or may take several weeks or months and occasionally years. The now famous Vatican exorcist Gariele Amorth explains all this in his two books: An Exorcist Tells His Story and An Exorcist: More Stories.