Pride is a season around a day, much the way that the Thanksgiving / Christmas is a season around specific days. A lot of families have to gather from far reaches together for Thanksgiving feast and Christmas Day, hence there's preparation and travel as well as food prep and gift gathering. Halloween is similar for those who take it seriously. It's a day for the kids but it's a month (or more!) for those who want to represent.

Pride ~~wasn't~~ isn't allowed everywhere, and in the beginning it only happened in those municipalities that had enough of a gay village (an LGBT+ community) to be a voting bloc. As a result there was a lot of travel arrangements from self-discovered people across the country. There were a lot of phone calls to friends to friends from last year if they'll still provide a place to crash.

The pride parade day is typically the weekend of June 28th (the anniversary of the 1969 Stonewall uprising). But sometimes the parade has to accommodate other circumstances in the city, so check with the organizers to get time and date confirmed.

A lot of those attending like to prepare their attire and accessories to look good. And if there are counter-protests or unfriendly law enforcement (more common than we like) then protest gear (first aid kits, bear spray, anonymizing bloc) may also be appropriate and add to the preparation schedule.