The Eastern Standard Time (EST) zone is a time zone that is 5 hours behind Coordinated Universal Time (UTC-5). It is primarily observed in the eastern part of the United States and parts of Canada. During daylight saving time, which typically runs from the second Sunday in March to the first Sunday in November, the time shifts to Eastern Daylight Time (EDT), which is UTC-4. EST is used in major cities such as New York, Washington, D.C., and Toronto. This time zone plays a significant role in business and communication, as it encompasses a large population and many financial markets.