The arena time you see in-game is not your local time but based on the server time.

Each server has their own server time, so finding the correct opening times for the arena may be challenging.

Please find below the opening times for Arena for each server:

Asia (Asia) server:

12:00 - 13:59 UTC+8

19:00 - 20:59 UTC+8

North American (NA) server:

12:00 - 13:59 PST / 13:00 - 14:59 PDT

19:00 - 20:59 PST / 20:00 - 21:59 PDT

European (EU) server:

12:00 - 13:59 UTC

19:00 - 20:59 UTC

Latin American (LA) server:

12:00 - 13:59 BRT

19:00 - 20:59 BRT

Oceania (OC) server:

11:00 - 12:59 UTC+10/AEST

20:00 - 21:59 UTC+10/AEST