How do I keep all-day events from appearing on the wrong date?

Start with the event itself, not by changing dates repeatedly. Open its details and check whether All day is selected. In Google Calendar on a computer, creating an all-day event means checking All day under the date and time before saving; Google says these events appear at the top of that day. If the box is not selected, the event may instead have start and end times, so note those before editing. [S2]

Next, write down the date you intended and the date shown in the calendar where you noticed the problem. Check the same event in its details and in the calendar view. That helps separate an event-setting issue from a display difference. Avoid changing the time zone as a first move: record its current setting so you can compare before and after.

It is worth checking, particularly if the event has times or is being viewed by people in different time zones. Google Calendar’s guidance says timed events are displayed in local time and that the calendar owner can inspect the primary time zone under Settings > General > Time zone. An event can also have a different time zone in its details. [S1]

For this troubleshooting pass, note the calendar’s primary time zone and any event-level time zone shown. Compare those settings with the date display you are investigating. Google’s time-zone guidance discusses timed-event conversion and daylight-saving effects, but it does not establish exactly how all-day events behave in every app or sync setup. Treat the time-zone check as a clue, not proof of the cause. [S1]

Compare the same event across views without changing several settings at once. Note the date in Google Calendar, the date in the other app, whether the event is marked all-day in each, and whether the other app is showing a copied or synced calendar. Then check the event details and the primary time zone in Google Calendar. Google’s instructions do not explain every cross-platform or synchronized-calendar discrepancy, so they cannot confirm which app is responsible. [S1] [S2]

A useful record might look like this:

Intended date: [date] | Google Calendar: [date] | Other app: [date] | All day: [yes/no in each] | Primary time zone: [setting] | Event time zone: [setting or not shown]

If only one app differs, keep that comparison and consult that app’s current help guidance or support. Don’t assume the event needs a new date until you know which view is showing the intended date.

Before editing, save your observations and confirm which calendar contains the event you intend to change. If you do edit it, change one setting at a time and recheck the date in the same views. For a new Google Calendar event on a computer, confirm the intended date and check All day before saving; Google’s instructions describe that as the all-day setup. [S2]

Use this short troubleshooting sequence:

1. Record the intended date and the date each app displays.
2. Confirm All day is selected in the event details.
3. Check the calendar’s primary time zone and any event-level time zone shown. [S1]
4. Compare the event in each relevant app or calendar view.
5. Change one setting at a time, then check whether the display changed.
6. If the discrepancy remains across apps, use the comparison notes when checking that app’s guidance.

This narrows down what to investigate, but it cannot guarantee a fix: Google’s guidance does not cover every all-day event display or synchronization setup.