Halloween event

When we give up all hope.

the same as they always do the Wednesday/Thursday before (depending on time zone) till the Wednesday/Thursday after.

As far as I understand, Halloween is the 31st of October. Do you want 3 weeks event?

No official announcement on a start date yet. Don't expect good communications about this from Niantic, they won't say anything until 2 days before at the most.

Last years Halloween event was the first ever Pokemon Go event and it ran 10/26 to 11/1. It featured increased candy and increased appreances from various spooky Gen1 mons.

Repeating the double candy event of last Halloween would be dull. So this year it will be "Bad Boys"-Halloween instead: If you encounter a "Bad" pokemon, all your collected candy will be taken away. If you do not have enough candy, your avatar's costume will be taken away, too.