"In August 2005, the U. S. Congress passed the Energy Policy Act. This act changes both the start date and the end date of daylight saving time (DST). When this act goes into effect in 2007, DST will start three weeks earlier and will end one week later than when it traditionally started and ended. Specifically, DST will start at 2:00 A.M. on the second Sunday in March and will end at 2:00 A.M. on the first Sunday in November." The summary is that you need to patch the operating system and Notification Services if you use it. The link has a fair amount of detail on how SQL Server deals with times.