During this time period, outbreaks of Clefairy will be occuring across both Paldea, where the species does not normally appear, as well as in Kitakami. Clefairy from these outbreaks will be more likely to be encountered with the Upbeat mark.
To participate in this mass outbreak event, players will need to download and install the latest update data following the release of The Teal Mask; and to download the latest Poké Portal News. If players have connected their Nintendo Switch system to the internet while playing Pokémon Scarlet or Violet, this should happen automatically. Players can also manually download the Poké Portal News by selecting Poké Portal from the X menu, and then selecting Mystery Gift, and then Check Poké Portal News.
While purchasing the DLC will not not be required to participate in this first mass outbreak event with Clefairy, future mass outbreak events may be restricted to Kitakami, or to other areas only unlocked by the DLC. As with Tera Raid events, in order to participate in limited-time mass outbreak events, players will need to have downloaded the latest update data and the latest Poké Portal News. A paid Nintendo Switch Online membership is not required to receive Poké Portal News.
- Sources
Mass Outbreak Events and Marks — Pokémon Scarlet and Pokémon Violet | Official Website
Encounter Clefairy in Paldea and Kitakami during a mass outbreak event after the release of The Hidden Treasure of Area Zero Part 1: The Teal Mask.scarletviolet.pokemon.comMass Outbreaks of Clefairy!
sv-news.pokemon.co.jp