Eastern Standard Time (EST) 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, including major cities like New York, Washington, D.C., and Atlanta. EST is used during the fall and winter months, typically from the first Sunday in November until the second Sunday in March. During the spring and summer months, many regions switch to Eastern Daylight Time (EDT), which is UTC-4. This change allows for longer daylight hours in the evening. The transition to and from EST and EDT is part of the practice known as Daylight Saving Time.