In Drupal 7 I have a date field in a content type that has the Time zone handling option set to "Date's time zone". Setting this option will render a drop down list of time zones in your date field.
I am trying to replace the list of core time zones with a smaller list for just the United States. I found this post which works perfectly for overriding the timezone drop down list on the user profile page. However, I have not been able to figure out how to get a reference to the timezone select list on a date field.
The timezone reference on the user profile field is:
$form['timezone']['timezone']['#options']
If you print the $form variable to the screen you can clearly see the time zones in the above reference.
What I can't figure out is where the timezone options are in the form variable for a date field. I would expect them to be in somewhere in
$form['field_event_dates']['und'][0]
I do see a default value for the timezone at
$form['field_event_dates']['und'][0]['#default_value']['timezone']
but I can't find "options" in there.
Any ideas where the "options" for the time zone are set in the form variable?