General DST information for the USA...
The rules for DST changed in 2007 for the first time in more than 20 years. The new changes were enacted by the Energy Policy Act of 2005, which extended the length of DST in the interest of reducing energy consumption. The new rules increased the duration of DST by about one month. DST will now be in effect for 238 days, or about 65% of the year, although Congress retained the right to revert to the prior law should the change prove unpopular or if energy savings are not significant. At present, Daylight Saving Time in the United States begins at 2:00 a.m. on the second Sunday of March and ends at 2:00 a.m. on the first Sunday of November.
In 2010, DST is from 2:00 a.m. (local time) on March 14th until 2:00 a.m. (local time) on November 7th. In 2011, DST is from 2:00 a.m. (local time) on March 13th until 2:00 a.m. (local time) on November 6th.
Daylight Saving Time or Standard Time Detector