Eastern Standard Time ( EST ), the time zone New York is in, which is 5 hours behind Greenwich mean Time (GMT) Central Standard Time ( CST ), the time zone Chicago is in, which is 6 hours behind Greenwich Meantime (GMT) Mountain Standard Time ( MST ), which is 7 hours behind Greenwich Mean Time (GMT) Pacific Standard Time ( PST ), the time zone Los Angeles is in, which is 8 hours behind Greenwich Mean Time (GMT)