Niantic has announced the details for the events taking place in October 2021 in Pokémon GO.

Coming in October: Pokémon GO Halloween 2021 and more!

Trainers, Get ready for the spookiest month of the year! There’s much to look forward to this October, including Pokémon GO Halloween, Pokémon in costumes, and a tie-in event with Pokémon the Movie: Secrets of the Jungle. The Season of Mischief Special Research story is still ongoing, so there will be more to learn about Hoopa this month, too!

October Research Breakthrough encounters
From Friday, October 1, 2021, at 1:00 p.m. to Monday, November 1, 2021, at 1:00 p.m. PDT (GMT −7), you’ll encounter Yamask in Research Breakthrough encounters.

Weekly 1 PokéCoin bundles
Every Monday in October, a one-time-purchase bundle containing a Remote Raid Pass and other items will be available in the shop for 1 PokéCoin.

Featured Pokémon in raids
The following Pokémon will be appearing in five-star raids throughout October.

• The Mythical Pokémon Genesect holding a Douse Drive will be appearing in five-star raids from Friday, October 1, 2021, at 10:00 a.m to Tuesday, October 12, 2021, at 10:00 a.m. local time. This will be this particular Genesect’s Pokémon GO debut! It will not be appearing as a Shiny Pokémon at this time.
• Altered Forme Giratina will be appearing in five-star raids from Tuesday, October 12, 2021, at 10:00 a.m. to Friday, October 22, 2021, at 10:00 a.m. local time. If you’re lucky, you might encounter a Shiny one!
• Darkrai that knows the attack Sludge Bomb will be appearing in five-star raids from Friday, October 22, 2021, at 10:00 a.m. to Friday, November 5, 2021, at 10:00 a.m. local time. This is the first time that Darkrai will be appearing in Pokémon GO with this attack! If you’re lucky, you might encounter a Shiny one!

In addition, the following Mega-Evolved Pokémon will be appearing in Mega Raids.

• Mega Gengar will be appearing in Mega Raids from Friday, October 1, 2021, at 10:00 a.m. to Friday, October 22, 2021, at 10:00 a.m. local time.
• Mega Absol will be appearing in Mega Raids from Friday, October 22, 2021, at 10:00 a.m. to Friday, November 5, 2021, at 10:00 a.m. local time.

Every Wednesday in October, a Raid Hour event will occur from 6:00 p.m. to 7:00 p.m. local time. The following Pokémon will be featured.

• Wednesday, October 6, 2021: Genesect holding a Douse Drive
• Wednesday, October 13, 2021: Altered Forme Giratina
• Wednesday, October 20, 2021: Altered Forme Giratina
• Wednesday, October 27, 2021: Darkrai that knows the attack Sludge Bomb

Pokémon Spotlight Hours
In the month of October, Pokémon Spotlight Hour will take place every Tuesday from 6:00 p.m. to 7:00 p.m. local time, and each will spotlight a different Pokémon and a special bonus!

• Tuesday, October 5, 2021: Drifloon will be in the spotlight, and you’ll earn twice the XP for evolving Pokémon.
• Tuesday, October 12, 2021: Gastly will be in the spotlight, and you’ll earn twice the Stardust for catching Pokémon.
• Tuesday, October 19, 2021: Gothita will be in the spotlight, and you’ll earn twice the XP for catching Pokémon.
• Tuesday, October 26, 2021: Murkrow will be in the spotlight, and you’ll earn twice the XP for evolving Pokémon.

October Community Day
Join us on Saturday, October 9, 2021, from 11:00 a.m. to 5:00 p.m. local time for a Community Day event featuring Duskull, the Requiem Pokémon! Duskull will be appearing more frequently in the wild. Evolve Dusclops (Duskull’s Evolution) during the event or up to two hours afterward to get a Dusknoir that knows the Charged Attack Shadow Ball. For more details, check out the October Community Day blog.

Upcoming events
Stay tuned for details about these upcoming events.

• Movie tie-in event: From ​​Friday, October 1, 2021 to Sunday, October 10, 2021, the latest Pokémon film, Pokémon the Movie: Secrets of the Jungle, releasing globally on October 8 on Netflix! In celebration, the Mythical Pokémon Zarude will be making its Pokémon GO debut! You’ll be able to encounter it by completing a free Special Research story—just be sure you log in during the event to claim the research. You can also look forward to lots of other in-game content inspired by the movie, including the return of Team Rocket members Jessie and James in Pokémon GO.
• Niantic’s Birthday: In celebration of Niantic’s birthday on Wednesday, October 6, 2021, log in to Pokémon GO to obtain a free box between 11:00 a.m. and 5:00 p.m. local time on that day!
• Pokémon GO Halloween returns: From Friday, October 15, 2021, to Sunday, October 31, 2021, costumed Pokémon will return for our annual spooky event! Look forward to costumed Pokémon appearing in the wild and a new Halloween-themed Special Research story. More details to come soon!

Please be aware of your surroundings and follow guidelines from local health authorities when playing Pokémon GO. Upcoming events are subject to change.

Source: https://pokemongolive.com/post/oct-2021-events/?hl=en