Part 1 of the Pokémon Go Winter Holiday event runs from Dec. 18-25 and part 2 runs from Dec. 25-31, with slight differences across them both.
Pokémon Go guide - Polygon
Pokemon GO Winter Holiday 2023: Field Research Tasks And Rewards
Pokémon Go guide - Polygon
Pokémon Go guide - Polygon
Wrap Up 2023 with an Epic Pokémon GO December Community Day Event, epic game pokémon
Pokémon Go Winter Holiday 2023 event guide - Polygon
Pokemon GO Winter Holiday 2023 Part 2: All You Need to Know
Winter Holiday Part 1 Event Overview & Field Research (Miko Graphics) : r/TheSilphRoad
Pokémon Go Winter Holiday 2023 event guide : r/GamesAreLife
Pokémon Go guide - Polygon
Pokemon GO Winter Holiday 2023: Field Research Tasks And Rewards
Pokémon Go guide - Polygon
Pokemon Go Winter Holiday Timed Research