https://www.gamespot.com/articles/pokemon-go-features-surfing-pikachu-in-its-first-c/1100-6456081/

Niantic's kicking off Pokemon Go's new year with a brand-new monthly event called Community Days. Beginning January 20, Niantic invites you to join other Pokemon Go players in your area.

Once a month, Pokemon Go players are encouraged to meet up in local parks. This not only gives everyone a chance to mix and mingle, but also a shot at catching the event's exclusive Pokemon. For just a few hours that day, one Pokemon with an exclusive move will be available to catch. Niantic did not specify if these event Pokemon are exclusive to the host parks, or anywhere around the world.