Cisco router support manual DST
The Energy Policy Act of 2005 officially took effect March 11, 2007. This basically extends daylight saving time. The chart built into the most routers is not going to be correct. In lieu of code upgrade you can manually specify the start and stop times. The example below sets the router/switch so DST starting 2nd Sun in March and ending the 1st Sun in November.
clock timezone EST -5 clock summer-time EDT recurring 2 Sun Mar 2:00 1 Sun Nov 2:00