We do have integrations with Google Calendar, Apple Calendar, Office 365 and Outlook.com. You can subscribe to your team's vacation calendar in any of of these calendars.
You can also subscribed to a new calendar that has leaves of your team by selecting the option "Public". Simply type in the command "Cal" into the AttendanceBot and integrate it with the calendar as per your requirement.
You can also access this link for reference : How to use cal command FAQ.
All calendars use local time of the user. If you are a distributed team with people in different time zones, you would see the time off requests for colleagues converted to your local timezone.
NOTE: For a half day vacation, we consider 12am to 12pm as first half and 12pm to 12am as second half.