[andrewaylett]

I disagree -- in this case, you should consider storing local time and the Olson tz it's due to be in. Microsoft make the mistake of doing it your way in Outlook, meaning that everyone had to update their calendars when the US changed their DST rules.

Events in the future are commonly scheduled relative to what the time is going to be in a specific place, regardless of how the tz rules change in the meantime. Automated actions in the future, however, may well need to be fixed to a UTC time. In short: you need to think about how your system will actually be used, and possibly store values differently depending on how they will be used.

On no account ever use a raw UTC+n offset.