A shared holiday calendar can help a team plan, but it cannot tell you which traditions each person observes. Nationality, a name or a photograph is not a reliable substitute for asking about availability.
Start with the operational question: when can people participate? Give colleagues a private way to flag dates or working arrangements that affect them. They should not need to explain a belief in a group chat to avoid being overlooked.
Keep the calendar useful and modest
Record relevant public holidays for the places where the team works, then invite optional additions. Verify dates using appropriate local sources when scheduling a particular event. Some observances follow calendars whose dates differ from year to year, so last year’s spreadsheet should not be treated as a permanent reference.
Distinguish an informational entry from a company closure. A date appearing on a calendar does not automatically tell employees whether the office is open, leave is required or a meeting will move. State those practical arrangements separately through the organisation’s normal process.
Avoid making one colleague the spokesperson
If you want to acknowledge an observance, do not assume the person associated with it wants to organise food, give a presentation or answer everyone’s questions. Offer participation without assigning cultural work by default.
For an important workshop, send proposed dates early and allow a confidential response. Where attendance conflicts cannot be avoided, consider another session, written input or a recording when appropriate. A recording alone may not provide the same opportunity to contribute, so ask what would be useful.
Finally, review who repeatedly absorbs inconvenient times or missed opportunities. Inclusion is not measured by the number of colourful labels in a calendar. It becomes visible when planning gives people a workable route to take part. Local leave entitlements and employer policies still need to be checked separately; a planning calendar is not legal advice about either.