The time 4 p.m. in the Eastern Standard Time zone is 9 p.m. in the Greenwich Mean Time zone. During daylight savings time, the GMT time is 8 p.m. when the Eastern Daylight Time is 4 p.m.
During the summer, which is when U.S. clocks are on daylight savings time in most states, GMT time is four hours ahead of EDT. During the winter, when daylight savings time is not in effect, GMT is five hours ahead of EST because one hour is gained in setting the clocks backward during the switch to standard time. The EST time zone covers the east coast of the United States.