http://en.wikipedia.org/wiki/North_American_Electric_Reliability_Corporation#NERC_today
Its strange to do this in the fall, in stead of the spring or summer.
http://www.spp.org/publications/13%20-%20CIPC%20Brief%20%28Harrell%20Conway%20Mar%202013%29%20V2.pdf
Some places start to get cold & even freeze overnight by mid November.
http://etheric.com/electric-grid-blackout-planned-november-13th-14th-2013
http://www.nytimes.com/2013/08/17/us/as-worries-over-the-power-grid-rise-a-drill-will-simulate-a-knockout-blow.html?pagewanted=all&_r=0
http://www.offthegridnews.com/2013/08/28/power-grid-down-drill-to-be-conducted-by-us-government,
http://www.youtube.com/watch?v=wVLIJDXNXoo
August 14
http://en.wikipedia.org/wiki/Northeast_Blackout_of_2003
July 13-14
http://en.wikipedia.org/wiki/New_York_City_blackout_of_1977
November 9, 1965 or 11-9
http://en.wikipedia.org/wiki/Northeast_blackout_of_1965
Of course, if something does go wrong perhaps those planning the drill can say that they thought that the fall is no colder than the spring. Yet, most people realize that its the other way around.
http://www.youtube.com/watch?v=eN4XICOyRb8
http://www.radioliberty.com/vemp.html