New features starting on June 28 at 1 p.m. PDT
- Shiny Alolan Pokémon — You’ll have a chance of encountering the following Shiny Alolan Pokémon: Rattata, Raticate, Sandshrew, Sandslash, Vulpix, Ninetales, Diglett, Dugtrio, Meowth, Persian, Geodude, Graveler, Golem, Grimer, Muk and Exeggutor.
- Team leader avatar items — Avatar items featuring the team leaders’ personal styles will be available in the Style Shop.
From June 28, 2019, at 1 p.m. PDT to July 6, 2019, at 1 p.m. PDT
- A familiar face returns to the party! — Once per day, you might have the chance to encounter a Pikachu wearing a party hat when you take a GO Snapshot photo! Pichu wearing a party hat will also be available to hatch from 7 km eggs.
From June 28, 2019, at 1 p.m. PDT to September 2, 2019, at 1 p.m. PDT
- Jump-Start Research — Looking to get up to speed with your research? Do you have a friend who wants to play but feels they’ve missed out on too much in Pokémon GO? Don’t worry! Trainers can complete new Special Research for helpful rewards that will jump-start their new or continuing adventures. This Special Research is only available this summer for players at level 10 or higher, so be sure to let your friends know about this opportunity to join in and get special rewards.
- Raid bonuses — Take down Raid Bosses faster and earn extra bonus Premier Balls to catch them with when you raid with friends.
- Decreased Stardust costs for trading — Trading Pokémon will cost ¼ less Stardust.
Source: Official Pokémon GO blog