Yes at the time of writing it looks like CME Group electronic trading is open as per usual. http://www.cmegroup.com/ Hurricane Sandy Update Oct 28, 2012 13:12 CDT New York City has issued a mandatory evacuation of Zone A, which includes CME Group's NYMEX World Headquarters and New York trading floor. As a result, the New York trading floor will be closed on Monday, October 29. We will open all of our electronic markets at their regularly scheduled times on CME Globex and CME ClearPort, our online electronic platforms. We will continue to update cmegroup.com as additional information becomes available.
http://www.cmegroup.com/hurricanesandy.html Hurricane Sandy Update Oct 29, 2012 3:00 CDT Hurricane Sandy Update Oct 29, 2012 3:00 CDT CME Group will reopen its U.S. equity index futures and options on futures markets today at 5:00 p.m. CT for overnight electronic trading. The equity index markets will close tomorrow morning October 30, at 8:15 a.m. CT for both the trading floor and CME Globex in coordination with the announced closure of the U.S. equity markets because of Hurricane Sandy.
It was so unnecessary to close the US market because of Sandy. I only have time to day trade a few days a week and Sandy mucked up my schedule...darn!
Sometime they have technical problems. so we can not say directly it is unnecessary or necessary. I can not believe they was wrong. They have geniuses in each field. So I think their decision is the best.