iPhone 5 and iPad Air calendar Time Zones
Check the following "Settings".  Make sure under "General > Date &amp; Time", that your iPhone is showing the correct "Time Zone"  You can either have the iPhone determine this automatically (by turning on the "Set Automatically" switch) or you can set it for a specific location.  Do note that in order for this to set itself automatically you need to have location services enables as well.  

The next thing I would check is "Settings > Mail, Contacts, Calendar" and make sure in the "Calendar" section that you've enabled "Time Zone Support".

All of this is covered in this Appple knowledge base article: http://support.apple.com/kb/ht4576

Hope this helps. Good luck!