What is a Raid Battle?
A Raid Battle is a cooperative gameplay experience that encourages Pokémon Go Trainers to work with each other to defeat an extremely powerful Pokémon known as the Raid Boss. This Raid Boss Pokémon will have much more CP than that of standard captured Pokémon.

For example, a single Trainer’s Pokémon may have 3,000 CP, while the Raid Boss may have 20,000 CP. Therefore, to successfully win a Raid Battle, players must team up (up to 20 players can team up in a single Raid) to defeat the powerful Raid Boss.
Why Should You Participate in a Raid Battle?
If both requirements are met, a Trainer may join a Raid once the Egg timer countdown reaches zero. Once the Raid begins players can choose their six Pokémon and begin attacking the Raid Boss. The goal is to reduce the HP of the Raid Boss to zero before the five minute timer runs out.


Why Should You Participate in a Raid Battle?
Defeating a Raid Boss will reward participants with a variety of rewards; some of which can only be obtained by defeating a Raid Boss. These rewards may include the following:
Rare Candy: Can be used on a Pokémon, and turns into that specific Pokémon’s Candy.
Golden Razz Berry: Can be used on wild Pokémon to greatly increase your chances of capture. These can also be used on a Pokémon assigned to a Gym to fully recover its motivation meter.
Technical Machine (TM): Can be used to permanently teach a Pokémon a new Fast or Charge Move.
Premier Ball: These Pokéballs are used specifically to capture Raid Boss Pokémon after defeating them. Once you run out of Premier Balls the Raid Boss will flee.
When/Where Do Raids Take Place?
Rare Candy: Can be used on a Pokémon, and turns into that specific Pokémon’s Candy.
Golden Razz Berry: Can be used on wild Pokémon to greatly increase your chances of capture. These can also be used on a Pokémon assigned to a Gym to fully recover its motivation meter.
Technical Machine (TM): Can be used to permanently teach a Pokémon a new Fast or Charge Move.
Premier Ball: These Pokéballs are used specifically to capture Raid Boss Pokémon after defeating them. Once you run out of Premier Balls the Raid Boss will flee.
When/Where Do Raids Take Place?
Raid Battles take place at Gyms. Before a Raid Battle begins, a large Egg with a countdown above it will appear atop of the Gym. During this time, players will travel to that specific Gym. Once the countdown reaches zero, the Raid Boss will be revealed and Trainers can begin the Raid.
How Do Raids Work?
How Do Raids Work?
A Trainer must meet a certain required Trainer Level and must have a Raid Pass to participate in a Raid. A Raid Pass can be acquired for free by visiting a Gym (one per day). You can also purchase a Premium Raid pass from the in-game shop if you wish.
If both requirements are met, a Trainer may join a Raid once the Egg timer countdown reaches zero. Once the Raid begins players can choose their six Pokémon and begin attacking the Raid Boss. The goal is to reduce the HP of the Raid Boss to zero before the five minute timer runs out.
If you do not defeat the Boss within the five minutes of alotted time, you may heal your Pokémon and try again, but the HP of the Boss will reset. If you cannot defeat the Raid Boss after one hour, the Raid will end you will not be given a chance to capture it.
Once a Raid Boss is defeated each Trainer that participated will receive rewards including Premier Balls. The more damage a Trainer has done to the Raid Boss the more Premier Balls he or she will earn. These premier balls can be used to capture Raid Bosses.
Raid Results From Lvl 40 Trainer
The following information was posted by sts_ssp on Reddit. He did five Raids in Tokyo on June 23, 2017.