Bun supports programmatically setting a default time zone for the lifetime of the
bun process. To do set, set the value of the
TZ environment variable to a valid timezone identifier.
When running a file with
bun, the timezone defaults to your system's configured local time zone.
When running tests with
bun test, the timezone is set to
UTC to make tests more deterministic.
process.env.TZ = "America/New_York";
Alternatively, this can be set from the command line when running a Bun command.
TZ=America/New_York bun run dev
TZ is set, any
Date instances will have that time zone. By default all dates use your system's configured time zone.
new Date().getHours(); // => 18 process.env.TZ = "America/New_York"; new Date().getHours(); // => 21