Question

I’m using FB api to get information about particular events. It works great but for some events it returns start_time without time zone offset.

For example: "start_time": "2012-09-20T16:00:00+0000" (timezone is empty). But should be "2012-09-20T19:00:00+0300"
https://www.facebook.com/events/416982425024750

Answer 1

Yes, you are correct, the timezone should be returned. However Facebook has made some changes (as they do) with regard to time management with events. Check out what the Events Documentation has to say –

Events Timezone Migration Note

Starting with the ‘Events Timezone’ migration, all event times are
always ISO-8601 formatted strings; the ‘date_format’ query string
modifier no longer has any effect. The following formats are now
returned, depending on the type of event:

• Date-only (e.g., ‘2012-07-04’): events that have a date but no specific time yet.
• Precise-time (e.g., ‘2012-07-04T19:00:00-0700’): events that start at a particular point in time, in a specific offset from UTC. This is
  the way new Facebook events keep track of time, and allows users to
  view events in different timezones.
• Local-time (deprecated, e.g., ‘2012-07-04T19:00:00’): legacy events that do not have any timezone information. This format is deprecated,
  but continues to be returned due to legacy events that are still in
  the system.

I believe that the specific event you are talking about simply has no way to calculate the timezone offset – possibly because no location was given.