The Feast of Santiago is ALWAYS a cause for a huge celebration. It is always on 25 July, regardless of what day that falls on. In 2024, it falls on a Thursday.
This means that most folks participating in this celebration, will take Friday off as a "bridge day." That fact will increase the crowds in Santiago - making a long weekend.
The city is crowded with tens (hundreds) of thousands of merrymakers. There are processions, festivals, concerts, parties.
On the night of the 24th leading to midnight, there are world-class fireworks around Santiago that can be viewed from multiple locations. They used to shoot them from the roof of the Raxoi Palace - Town Hall - opposite the Cathedral on the West Side. But, "short shots' caused damage to the roof.
Officials did not want to chance another Notre Dame type fire. So, the stopped this practice and decentralized the fireworks show to five launch areas around Santiago. Crowds still gather in Plaza Obradoiro at night to view the laser light show that is projected on the Raxoi Palace.
I consider it a good thing when I am able to be at Santiago to celebrate the Feast of Santiago. I hope you will too.
Hope this helps.
Tom