The account time zone is used to determine:
When the weekly schedule emails are sent to your team.
When your imported Google Calendar/Outlook events are displayed.
It can be set by the Account Owner or an Admin from the Hours & currency tab within the Team settings.
Tasks created directly in Float are set to the specific time they are scheduled, regardless of where your team is located (e.g., a task set for 2 p.m. displays at 2 p.m. for everyone it is assigned to).