Pokemon Go Shadow Legendary Pokemon Encounter to Change Each Month

Update: Trainers, Zapdos and Moltres Shadow forms have been added to Pokemon Go’s GM file.
If we follow the uno, dos and tres (one, two and three) pattern, we’ll most likely get Legendary Shadow Zapdos December 1-December 31 and next year, starting January 1, 2020, until January 31, 2020, we’ll get Shadow Legendary Moltres.
- November 2019 – Shadow Legendary Articuno
- December 2019 – Shadow Legendary Zapdos
- January 2020 – Shadow Legendary Moltres
Previous Story: Trainers, defeating the Team Go Rocket Boss Giovanni will grant you Shadow Legendary Pokemon and according to Niantic, this Shadow Legendary Pokemon will change on the 1st of each month.
At the moment of writing, Pokemon Go players who will defeat the TGR Boss Giovanni have a chance to catch Articuno as the Shadow Legendary Pokemon encounter. However, Shadow Articuno will be available to catch until November 30, and starting from December 1, a new Shadow Legendary Pokemon, most likely Zapdos or Moltres, will be available to catch only if a player defeats Giovanni.
Trainers, remember to defeat Giovanni by November 30th (local time) to encounter this month’s Shadow Legendary Pokémon!
The Shadow Pokémon you can encounter after defeating Giovanni changes on the 1st of each month. This is the case regardless of which month you received the Giovanni-related Special Research.
NOTE: Trainers can receive Giovanni Special Research once per calendar month. For example, if you complete your November Giovanni Special Research in mid-December, you’ll receive new Special Research shortly after. If you complete the November Research in mid-November, you’ll need to wait until midnight on December 1st (local time) to receive the Research again.