In celebration of the one year anniversary for Pokemon Go, Niantic is releasing another hatted Pikachu! From July 6 at 1:00 P.M. to July 24 at 1:00 P.M. (PDT) all wild Pikachu will be found wearing the famous hat that Ash wore in the anime series of Pokemon!
Along with the gift of another hatted Pikachu, you can get a chance to stock up with the special, limited-time Anniversary Box! The box will include Incubators, Max Revives, Ultra Balls, and Raid Passes at a discount in the in-game shop.
Happy hunting fellow players and remember to always be aware of your surroundings!
Source: Pokemon Go Live