Office 365 (Outlook on the Web) - Language and Time Settings
This article details how to customize language and time settings.
1. From the Outlook app, click the gear icon in the upper-right corner of the screen, then select Mail from the Settings menu.
2. Open the drop down menu for General in the options pane on the left side of the screen, then select Region and time zone.
4. Choose a language, set the date/time format, and select your current time zone, then click Save.