Niantic has announced the details for the Pokémon Day 2019 event in Pokémon GO which takes place on February 27th, 2019. Pokémon that Trainers encounter early on in their adventures through the Kanto region will appear more frequently in the wild including Shiny Pidgey and Shiny Rattata's.

Celebrate Pokémon Day and GO!

Trainers, We love Pokémon and we know you do, too! We would never pass up a chance to celebrate Pokémon. Pokémon Day happens every year on February 27. Do you know why this day is so special? It commemorates the launch of the first Pokémon video games in 1996. In celebration of #PokemonDay, we invited some familiar Pokémon originally discovered in the Kanto region to join us!

Date + Time:

• Feb. 26, 2019, at 1:00 p.m. PST to Feb. 28, 2019, at 1:00 p.m. PST (GMT −8)

Features:

• Pokémon that Trainers encounter early on in their adventures through the Kanto region will appear more frequently in the wild!
• Pokémon originally discovered in the Kanto region will be available to challenge in raids.
• Pikachu and Eevee wearing flower crowns will make a special appearance as Field Research encounters and in the wild.
• In celebration of Pokémon Day, you may even encounter Shiny Pidgey and Shiny Rattata!

Thank you for being part of our journey. Let’s celebrate Pokémon Day together!

Source: https://pokemongolive.com/en/post/pokemonday2019/