The event is rolling out in two phases, with some overlap between the two.
Here’s what they’re doing:
- Phase I: From December 25th to January 3rd, PokéStops will be more likely to dish out the baby Pokémon eggs they introduced earlier this month — Igglybuff, Clefa, Togepi, Pichu, Elekid, Smoochum, and Magby. Hatching eggs is the only way to get these Pokémon, but the egg distribution system is pretty random — so increasing the odds will definitely hook some people.
- The first time you spin a PokéStop each day during that period, you’ll get a single-use Incubator to hatch your eggs in — so if you do it each day during the promotion, that’s 10 single-use incubators. I wish they were the standard 3-use incubators — but hey, I’ll take it.
- Phase II: From December 30th to January 8th, they’re increasing the spawn rate of the starter Pokémon and their evolutions. That means more Charmander, Bulbasaur, and Squirtle (plus their evolutions. Charizards incoming!)
- During this period, Lures placed on PokéStops will last an hour instead of 30 minutes.
Meanwhile, that Santahat Pikachu that debuted a few weeks back should still pop up until December 29th.
Alas, Niantic has confirmed to me that there will be no doubling of XP or Stardust for this event — so if you’ve been sitting on a boatload of Pidgies all ready to evolve, it doesn’t look like December will be their time to shine.