How to account for time zone?

All dates and time is stored in UTC, when the user comes to the site I see its time zone (indicates when the check-in) and translate the date and time in the user timezone. There is nothing complicated.
The problem is this:
There are events where it is all day, then he has no time. Those dates I keep this: 2016-11-14 00:00:00, another field "allday" flag of 0 or 1.
And I don't know how to translate them?
July 2nd 19 at 16:54
1 answer
July 2nd 19 at 16:56
Do like a Google calendar, a separate place for such events
It starts depending on the time zone of the user at 00:00

If you have an event that occurs elsewhere, then it is better to specify the place and exact start time in local time

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