Tuesday 01 Jan New Year's Day
Monday 21 Jan Martin Luther King, Jr. Day
Monday 18 Feb Washington's Day
Friday 29 Mar Good Friday
Monday 27 May Memorial Day
Wednesday 03 Jul Early Close
Thursday 04 Jul Independence Day
Monday 02 Sep Labor Day
Thursday 28 Nov Thanksgiving Day
Friday 29 Nov Early Close
Tuesday 24 Dec Early Close
Wednesday 25 Dec Christmas Day
Note: Each market will close early at 1:00 p.m. on Wednesday, July 3, 2013, Friday, November 29, 2013 and Tuesday, December 24, 2013. Crossing Session orders will be accepted beginning at 1:00 p.m. for continuous executions until 1:30 p.m. on this date.
Source: http://www.nyse.com/Frameset.html?displayPage=/about/1022963613686.html