The Energy Policy Act of 2005 amends the Uniform Time Act of 1966 by changing the start and end dates of daylight saving time starting in 2007. Clocks will be set ahead one hour on the second Sunday of March instead of the current first Sunday of April. Clocks will be set back one hour on the first Sunday in November, rather than the last Sunday of October. This will make electronic clocks that had pre-programmed dates for adjusting to daylight saving time obsolete and will require updates to computer operating systems. The date for the end of daylight saving time has the effect of increasing evening light on Halloween (October 31).