The final Pokémon GO Fest 2019 is on the horizon this week in Yokohama Japan. To celebrate these festivities, Pokemon GO players globally will be able to take advantage of special bonuses and spawns. Starting August 6 at 10 a.m. JST to August 12 at 5 p.m. JST, a different hat costumed Pikachu will be available every day for you to capture! The featured Pokémon Poliwag will also be available in increased numbers and if you’re lucky you may encounter a shiny Poliwag.
Source: Pokemon GO (Mobile Application)