In 1884, the International Meridian Conference expanded the time zones to 24 around the world, with each running north to south and measuring roughly 15 degrees wide. Zone boundaries are uneven to account for the timekeeping convenience of populations within each zone.
Pacific Time refers to the time in the westernmost zone of the continental U.S. and applies to California, Washington, Oregon, Nevada and Idaho. This clock is typically eight hours less than Universal Time, Coordinated (UTC), formerly known as Greenwich Mean Time (GMT).
Central Time applies to the second of the U.S. time zones traveling east to west and includes such states as Texas, Mississippi and Illinois. To get this time, subtract six hours from UTC.
Standard time in all U.S. zones applies roughly only to the winter months. During the rest of the year, DST advances the clock by an hour, so that Pacific Time is UTC minus seven and Central Time is UTC minus five.
Pacific Time and Central Time stretches over zones in Canada and Mexico. However, Central Time also applies to Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Easter Island in Chile and the Galapagos in Ecuador.
