To change your server’s timezone per session you can use the following query:
set timezone TO 'GMT';
If you need to permanently update the timezone, find your postgresql.conf file in psql:
preston=# show config_file;
config_file
/Users/preston/Library/Application Support/Postgres/var-9.3/postgresql.conf (1 row)
Inside of postgresql.conf change your timezone
timezone = ‘US/Central’;
to
timezone = ‘UTC’;
Save and restart postgres.
Confirm the timezone is changed via
preston=# select current_setting(‘timezone’);
current_setting
GMT (1 row)