Trainers, Niantic and Pokemon Go announced the next Hidden Gems Season, and it looks like you can encounter Shiny Shadow Articuno from Shadow Raids almost every weekend.
Hidden Gems is the new Season of Pokemon Go. This Season runs from June 1-September 1, 2023, and during this period players can encounter new Pokemon, shiny forms, participate in cool events, battle and catch different Pokemon from Raids, Mega Raids, and Shadow Raids.
The first Shadow Pokemon to appear in Hidden Gems is Shadow Articuno. Starting June 10, Shadow Articuno will appear in Shadow Raids during weekends in June. Shadow Articuno can be shiny, so make sure to beat it and get yourselves a Shiny Shadow Articuno.
— Pokémon GO (@PokemonGoApp) May 30, 2023
We guess that Shiny Shadow Zapdos and Shiny Shadow Moltres are coming in July, and August, respectively.