https://www.gamespot.com/articles/next-pokemon-go-community-day-event-announced/1100-6458281/

With the fourth Community Day now behind us, Pokemon Go players can begin looking forward to next month's event. Niantic has announced the first details for May's Community Day, which is scheduled to take place on Saturday, May 19, and will feature another very popular Pokemon from the Red and Blue versions.

As always, the event begins at different times depending on where you live and will run for three hours. In the US, it kicks off at 11 AM PT / 2 PM ET and ends at 2 PM PT / 5 PM ET; in Europe and Africa, the Community Day takes place from 10 AM - 1 PM UTC; and in the Asia-Pacific region, the event lasts from 12 PM - 3 PM JST.