Building a Global Events Calendar That Doesn't Lie About Time Zones

Maxim Comms runs events across multiple continents, and the website we built for them needed a calendar that could list dozens of events, conferences, summits, delegate dinners, without ever showing a delegate the wrong time. That sounds like a solved problem. It is not, and most events websites get it wrong in ways nobody notices until someone shows up an hour late.

The standard approach, storing a single date and time and letting the browser convert it, works fine until an event spans a time zone change, daylight saving shifts mid way through a multi day conference, or a delegate is checking the calendar from a country that does not observe daylight saving at all. We have all seen a calendar confidently display a start time that is simply wrong for the viewer's actual location, with no indication anything might be off.

We built the calendar around the event's local time as the source of truth, not the visitor's. Every listing shows the time in the city where the event is actually happening, labelled clearly with that city's name, alongside a secondary line converting it to the visitor's detected local time. Neither number pretends to be the only correct one, because for a delegate flying in, the venue's local time is what actually matters once they land, while the converted time is what matters while they are still deciding whether to book flights.

Multi day events needed their own handling. A three day summit that crosses a daylight saving boundary in its host city cannot just apply one offset to the whole listing, so we built the underlying data model around actual calendar dates and local wall clock times in the venue's time zone, converting only at render time rather than storing a single UTC timestamp and hoping the maths held up across the whole event.

The result is unglamorous but correct, which is the entire point of a booking critical piece of infrastructure like this. Nobody praises a calendar for getting the time zone right. They only ever notice when it gets it wrong, usually while boarding the wrong flight.