In Mac OS X 10.5 through 10.5.4, your Mac may start up unexpectedly each day (at midnight UTC/GMT) even if it is not scheduled to start up in Energy Saver preferences in System Preferences. The local time when the computer may start up will vary depending on which time zone you are located in and whether or not daylight savings time is being observed. For example: Midnight UTC/GMT may be 5 p.m. Pacific Daylight Time (PDT) or 7 p.m. Eastern Standard Time (EST). This could happen after upgrading from Mac OS X 10.4 to Mac OS X 10.5 Leopard.
More from Apple OS X Support ...
