You'll find a variety of Pokémon spawning during the Pokémon Go December 2021 Community Day event. These Pokémon were featured during Community Days in 2021, and many of them were featured in the 2020 Community Day events. Looking for Charmander during the Community Day holidays of December 2021, you can only find him in one place. This guide explains how to catch Charmander in Pokémon Go's December 2021 Community Day event.
Charmander will not appear in the wild during this event. Instead, the only way you can find Charmander appearing in the wild is if you find it in a raid or hatch it from an egg. Of the two, raids are a little easier because you can see that Charmander has spawned, with a specific timer for when it disappears and goes away. So, all you have to do is challenge him to a battle, beat him and then try to catch him. For 2km eggs, though, you have to carry it around and hope to hatch it.
However, raid battles are more expensive because you need to have a raid pass or a remote raid pass on your character. If you don't have them, you are limited to the 2km eggs that appear in Pokéstops. You will need to visit a Pokéstop, turn the dial and hope that the 2km egg you get contains a Charmander inside.
Pokémon Go's December 2021 Community Day event will run from December 18-19, but bonuses for the event will run from December 17-20.