I will in Santo Domingo during this time and planned on attending. It will be my first time. What exactly is it?
Fiestas Patronales are yearly celebrations dedicated to the patron saint of a town or city, usually they close out several blocks around the town public park and have merengue and bachata performers and plenty of booze, the whole town and many outsiders enjoy the patronales, it is really fun.
There are different fiestas patronales for different towns and cities. As you are in the Southwest forum, are you looking for fiestas patronales in the southwest?