https://www.polygon.com/pokemon-go/2018/11/21/18107134/pokemon-go-december-community-weekend

To end the year on a high note, Pokémon Go’s final community event for the year in December will be a weekend long event that will increase the spawn rate of all the Pokémon from past community days. That means we’ll be seeing more Bulbasaur, Charmander, Squirtle, Pikachu, Eevee, Dratini, Chikorita, Cyndaquil, Mareep, Larvitar and Beldum in the wild!

The weekend will take place from Nov. 30 at 4 p.m. ET to Dec. 3 at 2 a.m. ET, giving you plenty of time to get out there and catch any Pokémon you need. Throughout the weekend, any of these special Pokémon will also get their special community day moves, which are as follows: