When it is 4 p.m. EST, it is 1 p.m. PST. Eastern Standard Time (EST) is the earliest time zone in the United States and comprises 17 eastern states and the District of Columbia. Eastern Standard Time is five hours behind Coordinated Universal Time, equivalent to Greenwich Mean Time.
Pacific Standard Time (PST) is the latest time zone affecting the lower 48 states. Parts or all of five states lie in the Pacific time zone, of which Los Angeles is the biggest city. Central Standard Time is one hour behind Eastern Standard Time, and Mountain Standard Time is one hour behind Central time. These time zones also apply to time in Canada and Mexico.