Question

What is the difference between config.time_zone and config.local_zone? Is there a situation when should both be set?

Answer 1

1) config.time_zone

Rails gives your ability to configure application time zone. It’s as easy as Time.zone = 'EST'.

So setting config.time_zone in your application.rb will eventually do the same. And this is the right thing to do since we don’t want to depend on server time zone.

In your application.rb (Rails 3) file, you can set the default timezone:

config.time_zone = 'Central Time (US & Canada)'  

2) config.local_zone

It displays the system local time.

So if you really must have local time in the db then lie to Rails by
setting config.time_zone to UTC, this tells it that it is to assume
that timestamps are already in UTC so it will not need to change them
to get them into what it thinks is UTC.

config.active_record.default_timezone determines whether to use Time.local (if set to :local) or Time.utc (if set to :utc) when pulling dates and times from the database. The default is :utc for Rails, although Active Record defaults to :local when used outside of Rails.