Richard Quadling wrote:
My heads trying to remember something I may or may not have known to start with.

If I hold datetimes in a DB in UTC and can represent a date to a user
based upon a user preference Timezone (not an offset, but a real
timezone : Europe/Berlin, etc.) am I missing anything?

The simple answer is ... No

Slightly more complex ...
If you are displaying timed events in the future and need to support multiple time zones, then using the browser TZ setting is useless, you need to work with a daylight saving setting instead. The site 'default' can either be UTC or it can be a particular timezone, but what will not work reliably is to offset from the browser information.

If all of your users are in the same timezone, then UTC without setting a timezone makes perfect sense and you even ignore even the daylight saving changes. Where the fun comes is where you are displaying times which straddle the daylight saving switches such as a train movement where the time you need to display jumps. In this case you have to use UTC for the movement, and display with the correct daylight saving offest.

Lester Caine - G8HFL
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