In a modern, distributed environment, your database server might be in Virginia, your application server in Ireland, and your user in Tokyo. If you use TIMESTAMP , a record created at "9:00 AM" becomes ambiguous. Was that 9:00 AM for the user or the server? TIMESTAMPTZ forces every entry into the universal language of UTC, ensuring that "now" means the same physical moment for every component of the system.
-- Insert the same "local" value INSERT INTO time_test VALUES ('2025-04-14 14:00:00', '2025-04-14 14:00:00'); postgres timestamp vs timestamptz
Furthermore, TIMESTAMPTZ handles transitions automatically. If you calculate the interval between two TIMESTAMPTZ points during a DST "spring forward" or "fall back" event, Postgres will return the mathematically correct number of elapsed hours. A plain TIMESTAMP will often be off by an hour because it lacks the context of the shift. The Case for TIMESTAMP : The Specialty Tool In a modern, distributed environment, your database server
If you are storing historical data (like birth dates) where the exact moment in time (UTC) is less important than the date on the calendar, date or timestamp is often preferred to avoid time zone shifting errors. TIMESTAMPTZ forces every entry into the universal language