Niantic have announced the details for the 13th Pokémon GO Community Day which takes place on February 16th, 2019 at 2:00 PM until 5:00 PM EST. The featured Pokémon for this day is Swinub. Swinub will appear in the wild more frequently for three hours that day. If you evolve Piloswine into Mamoswine during the event, the Mamoswine will know the move Ancient Power. The 3x Catch Stardust and 3-hour Lures bonuses will also be available that day.

Source: https://pokemongolive.com/events/community-day/