A new limited time event is on the way to Pokémon Sleep as New Moon Day #13 is set to run from May 16 to May 19, bringing themed bonuses and increased activity tied to the lunar cycle. Alongside the event, the New Moon Day Bundle Vol. 13 will be available soon, offering items that can help players progress during the event period. As with previous New Moon events, it is a short window focused on maximizing rewards through consistent sleep tracking and participation.
Source: Official Pokémon Sleep news and PokemonSleep.net