Niantic has announced the details for Pokémon GO Fest 2021: Raid Day which takes place on Sunday, July 18th, 2021, from 10:00 a.m. to 6:00 p.m. local time. Every Legendary Pokémon discovered in Pokémon GO so far will be appearing in five-star raids during Pokémon GO Fest 2021!

Pokémon GO Fest 2021: Raid Day will feature every Legendary Pokémon discovered in Pokémon GO so far!

Trainers, We’ve received reports that every Legendary Pokémon discovered in Pokémon GO so far will be appearing in five-star raids during Pokémon GO Fest 2021! Strange, right? This sort of thing hasn’t happened in the world of Pokémon GO before, so we’re just as puzzled as you are. Hopefully we’ll get some answers during the event as to why this is happening. Please note that it might be challenging to battle and catch every Legendary Pokémon in the allotted time frame, so plan accordingly!

Date + Time
Sunday, July 18, 2021, from 10:00 a.m. to 6:00 p.m. local time

• Legendary Pokémon will be appearing globally in five-star raids! Each Pokémon will be appearing during one of four themed hours that will be on a rotation throughout the event.
  • During Wind Hour, occurring from 10:00 a.m. to 11:00 a.m. and 2:00 p.m. to 3:00 p.m. local time, Mewtwo, Ho-Oh, Latias, Latios, Regigigas, Altered Forme Giratina, Cresselia, and Therian Forme Tornadus will be appearing in five-star raids.
  • During Lava Hour, occurring from 11:00 a.m. to 12:00 p.m. and 3:00 p.m. to 4:00 p.m. local time, Moltres, Entei, Regirock, Groudon, Heatran, Reshiram, Therian Forme Landorus, and Yveltal will be appearing in five-star raids.
  • During Frost Hour, occurring from 12:00 p.m. to 1:00 p.m. and 4:00 p.m. to 5:00 p.m. local time, Articuno, Suicune, Lugia, Regice, Kyogre, Palkia, and Kyurem will be appearing in five-star raids. Plus, Uxie, Mesprit, and Azelf will be appearing in five-star raids in the regions that they normally appear in!
  • During Thunder Hour, occurring from 1:00 p.m. to 2:00 p.m. and 5:00 p.m. to 6:00 p.m. local time, Zapdos, Raikou, Registeel, Rayquaza, Dialga, Therian Forme Thundurus, Zekrom, and Xerneas will be appearing in five-star raids.
  • Mythical Pokémon will not be appearing in five-star raids.
  
  

While all Trainers will be able to participate in this raid extravaganza regardless of whether they have a Pokémon GO Fest 2021 ticket, ticket holders will enjoy the following benefits.

• Earn an extra 10,000 XP for winning a Raid Battle.
• Spin Gym Photo Discs to earn up to 10 Raid Passes. These can be used for in-person raids.
• Complete Timed Research to earn up to eight Remote Raid Passes. These can be used to join a raid remotely.
• Pick up an event bundle containing three Remote Raid Passes! The bundle will be available in the shop on Sunday, July 18, 2021, from 10:00 a.m. to 6:00 p.m. local time.

Tickets are available now! Remember: there’s a ton to look forward to with raids this summer! Be sure to check out all the exciting updates to raids we have in store.

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/pokemongofest2021-raidday/?hl=en