US Time Zones


The United States make use of nine standard time zones. Yes, you read it well, nine stantard time zones!

Here they are, please note that UTC stands for Universal Time Constant:

  • Atlantic Standard Time (UTC-4)
  • Eastern Standard Time (UTC-5)
  • Central Standard Time (UTC-6)
  • Mountain Standard Time (UTC-7)
  • Pacific Standard Time (UTC-8)
  • Alaska Standard Time (UTC-9)
  • Hawaii-Aleutian Standard Time (UTC-10)
  • Samoa Standard Time (UTC-11)
  • Chamorro Standard Time (UTC+10)


Now, of all these time zones, the Eastern Standard Time, also known as EST, is the most popular one. After the Eastern Standard Time, the Pacific Standard Time, also known as PST, is the most popular zone.

Why are these two Standard Times the most used ones? The reason is due to the fact that the East Coast and the West Coast are by far the most industrialised regions of the United States.

Now, as you can see from the picture posted above, if it’s 6PM according to the Eastern Standard Time, it will be 5PM according to the Central Standard Time, it will be 4PM according to the Mountain Standard Time, and it will be 3PM according to the Pacific Standard Time. Please note that however it would only be 2PM if you were in Alaska, because of the Alaskan Standard Time, and it would only be 1PM if you were in the Hawaii or in the Aleutian Islands. Even though the Aleutian Islands are part of the state of Alaska, they follow their own standard time, which is the Hawaii-Aleutian Standard time.

These six Time Zones are very easy to remember as they include very popular zones, but there are still three Time Zones:

The Atlantic Standard TIme, also known as AST, is a UTC-4 region, this means that if it were 6PM according to the the Easterna Standard Time, it would already be 7PM according to the Atlantic Standard Time. But why should this Standard Time be part of the nine Standard Times of the United States, if no portion of the US is located in the Atlantic Standard Time Zone? This is due to the fact that Puerto Rico, an unincorporated terrory of the USA, is actually located in the Atlantic Standard Time Zone. An unincorporated territory is an area controlled by the United States government, but which is actually not part of the US proper.

The Samoa Standard Time, also known as SST, is a UTC-11 region, this means that if it were 6PM according to the EST, it would only be midnight in the Samoa Standard Time. American Samoa, the Midway Islands, and the islands of Palmyra, Jarvis, and Kingman Reef use this specific time zone. Of all these territories only the island of Palmyra is an incorporated territory of the US.

The Chamorro Standard Time, also known as ChST, is a UTC+10 region, ten hours ahead of the UTC, which means that if were 6PM according to the Eeastern Standard Time, it would apparently be only 9AM according to the ChST, however this zone would be one day ahead compared to the Eastern Time Zone. To make it simpler, the Chamorro Standard Time is 15 hours ahead of the Eastern Standard Time. This time zone includes the territories of Guam and the Northern Mariana Islands. These are both unincorporated territories of the US.

As you can see it wasn’t that hard to learn all the Standard Time Zones of the US.

If you want to know how the US States are divided according to their time zone, click here.

If you want to know the time zone of the most famous American cities, click here.