Pokemon Go's September Community Day Features Roggenrola

gamespot.com:

Pokemon Go's upcoming community day will be held on September 18 from 2 PM to 5 PM local time. Roggenrola, the Mantle pokemon, will headline the event. And as usual, there will be community day bonuses like double Catch Candy, reduced hatch distance, and raid bonuses.

See below for a full detailed list of what September's community day has in store.

Pokemon Go has a number of special events lined up for September. A special Psychic Spectacular event goes live on September 6 and players will have an increased chance of catching Deoxys and Mega Alakazam. A Clefairy's rate-up is also occuring on September 10 in honor of the harvest moon, and trainers will encounter wild Clefairys at an increased rate.

Season of Light also kicked off on September 1 and will center around Cosmog, Alolan Nebula Pokemon.