The Pokémon GO Battle Night event takes place on Sunday, July 11th, 2021, from 6:00 p.m. to 11:59 p.m. local time and players have the chance to battle for triple Stardust rewards.

Fan the Flames of Competition during GO Battle Night in Pokémon GO

GO Battle Night will take place the evening of July 11, offering you the chance to battle for triple Stardust rewards.

The heat of battle is the perfect opportunity for Pokémon GO Trainers to test their mettle and prove they have what it takes to be the very best. And there's no better time to battle than the GO Battle Night event taking place on Sunday, July 11, 2021, from 6:00 p.m. to 11:59 p.m. local time.

During GO Battle Night, you can participate in a whopping 20 battle sets for a total of 100 battles—that's quadruple the usual daily limit of five battle sets! Best of all, you'll earn triple Stardust rewards for winning battles, completing battle sets, and ranking up in the GO Battle League. You can use that Stardust to power up Pokémon for future battles.

Battle hard, Trainers!

Source: https://www.pokemon.com/us/pokemon-news/fan-the-flames-of-competition-during-go-battle-night-in-pokemon-go/