How to convert UTC time to Local Time

In my opinion, Local to UTC time conversion should be done nearer to UI level. That is, you should pass UTC time to your query and the time should be converted later when it is displayed to the user.
 
Doing the conversion in code will simplify SQL queries and thus probably improve overall performance. Also, it would be much more easier to allows the user to select which time zone to use. Most of the time, the time zone is only a display property and all the logic is done with UTC time.