Working with Different Timezones in Go and PostgreSQL

When your application serves users across multiple timezones — or integrates with data sources that record timestamps in varying timezone contexts — handling time correctly becomes critical. A subtle mismatch between your application’s timezone and your database’s timezone can cause silent data corruption: queries return incorrect result sets, scheduled jobs fire at wrong times, and bugs are nearly impossible to reproduce in local development.

Here are the strategies I follow to keep time data consistent and make retrieval predictable.

Core Strategies

1. Store all timestamps in a single timezone. UTC is the standard choice. If you’re using PostgreSQL, set the default database timezone to UTC explicitly rather than relying on system defaults.

2. Convert to the database timezone before writing. If your database is set to UTC, every timestamp must be converted to UTC before it’s inserted. Never store local time directly.

3. Convert query parameters to the database timezone before reading. When filtering by time for a specific timezone, convert the query bounds to UTC first — otherwise you’ll get the wrong result set.

4. Convert result sets to the requested timezone after reading. Transform timestamps back to the appropriate local timezone at the application layer, after the query returns.

Example

Consider a flights table with departure_time and arrival_time fields, where departures and arrivals may originate from countries in different timezones.

The code below demonstrates how to convert, insert, query, and transform these timestamps correctly in Go: