Pokemon Go plans to host a Rayquaza Raid Weekend later in March.
Recently, Pokemon Go announced a new "Special Raid Weekend" event featuring the Legendary Dragon/Flying-type Pokemon Rayquaza.
During the three day event, Rayquaza will be added to the Raid Boss pool so that players will have more chances at battling the Pokemon.
According to comicbook.com, the event will take place between March 15th through March 18th.