NSString *openingHour = @"15:05:35 ";
NSDateFormatter *workingHoursFormatter = [[NSDateFormatter alloc] init];
NSTimeZone *timeZone = [NSTimeZone timeZoneWithName:@"UTC"];
[workingHoursFormatter setTimeZone:timeZone];
[workingHoursFormatter setDateFormat:@"HH:mm"];
NSDate *openingTime = [workingHoursFormatter dateFromString:openingHour];
Can you try the above code it works for me , alter the date format to your need