[halostatue]

I would go as far to say that the timezone stored should be a named, geographically-based timezone (e.g., America/New York or Canada/Eastern) as opposed to a timezone offset. (If you store the timezone as EDT or EST, you have still encoded -0400 or -0500.)

[Avernar]

The postgres documentations says exactly that. Other databases might do something else so it's best to read the documentation.