Facebook graph API: Event timezone, time - ios

Question

I am currently having a problem with getting the correct time for an event via Facebook's graph API. There are some events showing the correct time and some are not. Even if I am calculating the timezone wrongly, it just doesn't make sense to me.
For example I have the following three events: "Brunch", "Champions league finale" and "Pfingst-Tanz". That's what the graph API gives back:
{
"data": [
{
"name": "Pfingst-Tanz",
"start_time": "2012-05-27T10:00:00",
"end_time": "2012-05-27T14:00:00",
"timezone": "Europe/Berlin",
"location": "...",
"id": "..."
},
{
"name": "Championsleague Finale",
"start_time": "2012-05-19T11:45:00",
"end_time": "2012-05-19T14:45:00",
"timezone": "Europe/Berlin",
"location": "...",
"id": "..."
},
{
"name": "Muttertagsbrunch",
"start_time": "2012-05-13T10:00:00",
"end_time": "2012-05-13T14:00:00",
"location": "...",
"id": "..."
}
],
"paging": { … }
}
On the Facebook page it shows:
Pfingst-Tanz 19:00 (07:00 pm)
Champions league finale 20:45 (8:45 pm)
Brunch 10:00 (10:00 am)
Which results in:
Pfingst-Tanz: Facebook page correct, API incorrect or TZ incorrect in my app
(Champions league finale: don't know, never mind)
Brunch: Facebook page and API correct and same
This just does not correspond to each other. From what I understand it has to be either all wrong or none wrong, but not just 1/3 or 2/3 events. Does anyone have an idea, or am I just too blind to see something?

Answer 1

Your "Brunch" event doesn't include a time zone, so it can't be adjusted to the user's local time zone, which is what I assume Facebook is doing.
It's not immediately clear to me whether the start_time and end_time values are meant to represent the local start/end times (in the given time zone) or the UTC start/end times, but that should be easy enough to work out based on the data (and documentation, hopefully). I suspect it's the UTC start/end when there's a time zone specified, but the local start/end otherwise.