To set the Time Zone from the command line, use:

RunDLL32 shell32.dll,Control_RunDLL %SystemRoot%system32TIMEDATE.cpl,,/Z

where is the data value of the Display Value Name, or the Std Value Name ,at HKEY_LOCAL_MACHINESoftwareMicrosoftWindows NTCurrent VersionTime Zones.

You can also use:

Control.exe %SystemRoot%system32TIMEDATE.CPL,,/Z .

Example:
RunDLL32 shell32.dll,Control_RunDLL %SystemRoot%system32TIMEDATE.cpl,,/Z US Eastern Time

NOTE: You do NOT encapsulate the time zone string in quote (“) marks.

• Set Time Zone From Command Line in Windows 2003, XP and 2000
• Set Time Zone From Command Line in Windows 7 and Windows 2008