The U.S. Energy Policy Act of 2005, passed by the U.S. Congress July, 2005, extended Daylight Saving Time (DST) in the U.S. by approximately four weeks. As a result, beginning in 2007, DST will start three weeks earlier on March 11, 2007, and end one week later on November 4, 2007, resulting in a new DST period that is four weeks longer than previously observed. These four weeks are referred to in this article as the "extended DST period". Visit MSN Encarta for more general information on DST.

Previously DST started on:	With the new law, DST will start on:
First Sunday of April (04/01/07)	Second Sunday of March (03/11/07)

Previous DST ended on:	With the new law, DST will end on:
Last Sunday of October (10/28/07)	First Sunday of November 11/04/07

Unless certain your clock may be off by one hour, and certain applications running on your Windows based computer may not in updates are applied to your computer, it is possible that the time zone settings for your computer's system clock may be incorrect during this four week period. This depends on where you live and which time zone you have selected. To see the time zone settings on your computer, follow these directions.


When your time zone settings are incorredisplay the correct time. To address this, Microsoft is providing many free updates and tools that will update your system automatically.

While the change in daylight saving time applies to U.S. and Canada, the change may impact customers based outside North America. Companies or organizations with operations, customers or vendors based in North America may be affected. In addition customers who interact or integrate with systems that are based in North America or rely on date/time calculations may be impacted. Customers who live outside North America and yet are impacted should follow the guidance provided on this site to prepare for the adjusted daylight saving time.

Please note that Mexico will not be following the new DST 2007 rules with the U.S. and Canada. Accordingly such systems configured to use U.S. time zones (for example, Pacific Time) will need to change their system configurations to use the new Mexico time zones. -Microsoft



Top Issues

• Microsoft products affected by 2007 daylight saving time changes
• What end users can do to ease the transition
• General sequence of update actions & special considerations
• Supporting the DST changes on Windows operating systems
• Preparing other Microsoft software products for the 2007 DST changes