If you don't set the time zone, the time zone is set to (UTC) Monrovia, Reykjavik. There's no method for admins to set up the time zone setting in advance in Outlook Web App for all users.
The following screen shot shows the OWA (Outlook Web App) sign-in screen in Office 365 - the first time you log into your college email
To change the time zone to the correct setting in OWA (Outlook Web App), follow these steps:
For more information about how to set the time zone in Outlook Web App, see Regional settings