After you have completed the Request Daybreak, you will start getting Massive Mass Outbreaks. These only appear during Rainstorms or Snowstorms in each area and are only available for a limited time.
These Massive Mass Outbreaks will cause massive spawns of various Pokémon across the entire area, but unlike the Mass Outbreaks, these are time limited and when the storm ends, the outbreaks go as well. When you enter the area, you have no idea what Pokémon is available as an Outbreak.
The Massive Mass Outbreaks last 7 minutes 75% of the time, 9 minutes 15% of the time and 11 minutes 10% of the time.
Each Mass Outbreak has between 8 and 10 Pokémon and a slim chance of a second wave coming through. These waves include evolved versions of the Pokémon or Alpha variants. The second wave will have between 6 and 8 Pokémon in. When they decide the second wave, it pulls from several different tables. Either a wave with the Evolutions of the Pokémon if applicable, a table with just Alphas of those Pokémon or one with Alphas of the Evolved forms of those Pokémon. If the Pokémon doesn't evolve, it will just pull a table for the Alpha of that Pokémon
|Type of Wave||Rarity|
|Evolved Alpha Pokémon||9%|
Massive Mass Outbreak tables in each area all have a special rate with there being Common and Rare spawns. Whenever a Massive Mass Outbreak happens on a map, 1 of them is from the Rare 1 Category, another from Rare 2 and the restr will be from Common. This means some Massive Mass Outbreaks are rarer than others.
Like Mass Outbreaks, there is an increased Shiny Chance, but this is at a lower rate than the Mass Outbreaks due to the number of Pokémon that appear.
|Base||13 in 4096|
1 in 315.54
|Species Research Level 10||14 in 4096|
1 in 293.04
|Species Research Perfect||16 in 4096|
1 in 256.47
|Species Research Level 10 & Shiny Charm||17 in 4096|
1 in 241.41
|Species Research Perfect & Shiny Charm||19 in 4096|
1 in 216.05