NSDateFormatter returns nil for specific date only in certain time zones

Question

Given this code:

NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setDateFormat:@"yyyyMMdd"];
NSArray *datesArray = @[@"20130326", @"20130327", @"20130328", @"20130329", @"20130330", @"20130331", @"20130401"];
for (NSString *dateString in datesArray) {
    NSDate *date = [dateFormatter dateFromString:dateString];
    NSLog(@"date: %@", date);
}

This is the output in my timezone (EST):

date: 2013-03-26 04:00:00 +0000
date: 2013-03-27 04:00:00 +0000
date: 2013-03-28 04:00:00 +0000
date: 2013-03-29 04:00:00 +0000
date: 2013-03-30 04:00:00 +0000
date: 2013-03-31 04:00:00 +0000
date: 2013-04-01 04:00:00 +0000

When I go to Settings -> General -> Date & Time, and set the timezone to Amman, Jordan (GMT+3), this is the output for the same code:

date: 2013-03-25 22:00:00 +0000
date: 2013-03-26 22:00:00 +0000
date: 2013-03-27 22:00:00 +0000
date: (null)
date: 2013-03-29 21:00:00 +0000
date: 2013-03-30 21:00:00 +0000
date: 2013-03-31 21:00:00 +0000

Why?

Answer 1

I don't know for sure, but it is probably not a coincidence that the clocks change in Amman, Jordan on the 28th: http://www.evi.com/q/when_do_the_clocks_change_in_amman_jordan

My suspicion is that the clocks jump from 2013-03-28 21:59:59 to 2013-03-28 23:00:00, so the time 2013-03-28 22:00:00 doesn't exist in the Amman, Jordan time zone.