Once you login, go to the forum (well, you're already here if you're reading this!), and click on the link at the top of the screen that says "Profile" (It's next to Usergroups). If you scroll down halfway, you'll see the section on setting your own local time.
Hope this helps!
Disclaimer: Any information you find on this site should not be considered medical advice. All decisions should be made with the consent of your doctor, otherwise you are at your own risk.