Niantic has announced the Pokémon GO Community Day dates for September to November 2023 as well as some event days.

Save the dates for next Season’s Community Days!

Trainers,
Now that the final Community Day of Pokémon GO: Hidden Gems is behind us, we’d like to share next Season’s Community Day dates!

• Saturday, September 2, 2023 (Community Day Classic)
• Saturday, September 23, 2023
• Sunday, October 15, 2023
• Sunday, November 5, 2023
• Saturday, November 25, 2023 (Community Day Classic)

Community Days aren’t the only events on the horizon—here are the dates for additional in-game events coming next Season!

• Sunday, September 17, 2023
• Saturday, September 30, 2023
• Saturday and Sunday, October 7–8, 2023
• Saturday, October 21, 2023
• Saturday, November 11, 2023

Stay tuned for more details about September Community Day and beyond!

Source: https://pokemongolive.com/post/season-savethedate-s12?hl=en