Each time zone is numbered from -1 to -11 to the west of the Greenwich Time Line, which means their times are 1 to 11 hours before the GMT (Greenwich Mean Time). The time zone to the east is numbered from +1 to +11 of the Greenwich Time Line, which means they are 1 to 11 hours later that the GMT.
The International Date Line is .. If you were traveling west of this line, you would gain a day. If you were traveling east of this line, you would lose a day.
Another way to look at it would be that the United States is several hours behind the countries west of this line.
There are 24 standard times zones. These time zones are divided by lines of longitude. Since the earth rotates 15 degrees in one hour, each time zone covers 15 degrees of longitude.
What Time Is It?
Select the correct time from the drop-down menus below. Click on the link below to check your answers.
1. If it is 7:00 p.m. in New York, New York, what time is it in Los Angeles, California?
2. If it is 2:00 a.m. in Little Rock, Arkansas, what time is it in Portland, Oregon?
3. If it is 5:30 a.m. in Topeka, Kansas, what time is it in Albuquerque, New Mexico?
4. If it is 2:59 a.m. in Detroit, Michigan, what time is it in Geneva, Switzerland?
5. If it is 10:30 a.m. in Dallas, Texas, what time is it in Jakarta, Indonesia?
Pacific Mountain Central Eastern
Western N. Dakota
Western S. Dakota
Eastern N. Dakota
Eastern S. Dakota
District of Columbia
The Prime Meridian is just opposite of the International Date Line. A day is added when you cross westward over the International Date Line. A day is subtracted when you cross eastward over the International Date Line.
The United States is divided into nine time zones. From west to east, they are: Chamorro (ChST or UTC+10), Samoa (SST or UTC-11), Hawaii-Aleutian (HST), Alaskan (AKST), Pacific (PST), Mountain (MST), Central (CST), Eastern (EST), and Atlantic (AST).
The chart above shows locations around the world and where they appear in each time zone.
Example 1: If it is 10:25 a.m. Sunday in Los Angeles, California, it would be 7:25 p.m. Sunday in Cairo, Egypt since Los Angeles is 9 hours behind Cairo.
Hint: Los Angeles's time zone is UTC-7, and Cairo's time zone is UTC+2. If we were to count the time zones between the two locations, moving from left to right as the arrow shows above the chart, we would see that they are 9 time zones apart.
UTC - Universal Time Coordinated
Example 2: If it is 12:02 p.m. Thursday in Chicago, Illinois, it would be 3:02 a.m. Friday in Sydney, Australia since Chicago is 16 hours behind Sydney.
Hint: Chicago's time zone is UTC-6, and Sydney's time zone is UTC+10. If we were to count the time zones between the two locations, we would see that they are 16 time zones apart.
Example 3: If it is 7:16 a.m. Tuesday in Honolulu, Hawaii, it would be 11:16 p.m. Tuesday in Dhaka, Bangladesh since Honolulu is 16 hours behind Dhaka.
Hint: Honolulu's time zone is UTC-10, and Bangladesh's time zone is UTC+6. If we were to count the time zones between the two locations, we would see that they are 16 time zones apart.
Time Zones Around the World