Strefy czasowe można zastosować do NSDateFormatter, z której można wygenerować zmienne NSDate zróżnicowane o różnicę czasu.
NSString* input = @"2013-08-03T05:38:39.590Z";
NSString* format = @"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";
// Set up an NSDateFormatter for UTC time zone
NSDateFormatter* formatterUtc = [[NSDateFormatter alloc] init];
[formatterUtc setDateFormat:format];
[formatterUtc setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
// Cast the input string to NSDate
NSDate* utcDate = [formatterUtc dateFromString:input];
// Set up an NSDateFormatter for the device's local time zone
NSDateFormatter* formatterLocal = [[NSDateFormatter alloc] init];
[formatterLocal setDateFormat:format];
[formatterLocal setTimeZone:[NSTimeZone localTimeZone]];
// Create local NSDate with time zone difference
NSDate* localDate = [formatterUtc dateFromString:[formatterLocal stringFromDate:utcDate]];
NSLog(@"utc: %@", utcDate);
NSLog(@"local: %@", localDate);
[formatterUtc release];
[formatterLocal release];
możliwy duplikat [Jak przekonwertować czasu do strefy czasowej urządzenia iPhone?] (Http://stackoverflow.com/questions/1081647/how-to-convert-time-to-timezone-of-thone-device) –