# Travel >> Travel Preparation >> General Travel Prep

How to Calculate Continental Time in the USA

Except for those in Arizona and Hawaii, the people in the rest of the country have become used to the change in time that occurs in the spring and fall. Daylight saving time shifts the clocks forward or backward by one hour to maximize the number of hours of sunlight in our day. The continental United States of America, or continental USA, covers a large portion of the earth's surface, so this large distance separates sunrise and sunset by three hours between the East Coast and the West Coast. In 1883, the government broke the country into four distinct time zones so that each part of the country begins the day at approximately 8:00 a.m. Figuring out the time in each of the time zones can become confusing, but you can calculate it based on Greenwich Mean Time.

Instructions

- 1
  Locate the four time zones for the continental USA. The four zones are Pacific Standard Time, Mountain Standard Time, Central Standard Time and Eastern Standard Time.
- 2
  Look up the Greenwich Mean Time.
- 3
  Calculate the time on the East Coast by subtracting five hours from the time in Greenwich.
- 4
  Calculate the time for the other time zones in the USA. Subtract one hour from the East Coast time to find the time in the Central Time Zone. Subtract two hours from the East coast time or one hour from the time in the Central Time Zone to find the time in the Mountain Time Zone. Subtract three hours from the East coast time, two hours from the Central Time Zone time or one hour from the Mountain Time Zone time to find the time in the Pacific Time Zone.
- 5
  Calculate the time in Arizona. Most of the state of Arizona does not participate in daylight saving time. The only region in Arizona that does participate is the Navajo Nation Indian Reservation. Arizona is seven hours behind Greenwich Mean Time all year long.