Pokémon Day

Pokémon Day is an annual event in Pokémon GO that takes place around the day of February to celebrate the anniversary of the  franchise.

2017 Event
This event took place between February and March, 2017.

Features
To celebrate Pokémon Day, any Pikachu that were encountered in the wild wore a festive party hat. Any Pikachu captured during the event keeps its hat forever and every Raichu evolved from Pikachu with such hat have the same hat as well.

2018 Event
This event took place between February and February, 2018.

Features
Festive party hat Pikachu returned and offered 300 Stardust per catch, but this time trainers could also hatch Pichu with the party hat and also there was possibility of getting shiny variation of any member of Pikachu family with this party hat.