US time zones are something new settlers need to know, since this vast country spans several different time zones. Understanding how to calculate the time helps with communication and scheduling. This article explains US time zones and how to calculate time between states.
US time zones: multiple time zones within one country
Because its territory stretches so far from east to west, the continental US spans several different time zones. This means that at the same moment, the time on the East Coast and West Coast can differ by several hours.
The main time zones on the mainland include Eastern, Central, Mountain, and Pacific time, with the time difference increasing from east to west. There are also separate time zones for certain territories.
Effects on daily life
Time zone differences affect communication within the US and with Vietnam. When calling relatives in another state or in Vietnam, you need to account for the time difference to avoid calling at an inconvenient hour.
This also matters at work when dealing with people in other states. Understanding time zones helps in scheduling meetings and work reasonably.
A note on daylight saving time
Many areas in the US observe daylight saving time (adjusting clocks seasonally), which changes the time at certain points in the year. Some places do not observe it. This can cause confusion if you are not aware of it.
You should refer to information about time and an overview of the United States to understand the time zones and be aware of them when calculating time between regions.
Summary
US time zones include several zones (Eastern, Central, Mountain, Pacific) due to the country’s vast territory, with the difference increasing from east to west. Many places observe daylight saving time. You should keep track of the time difference for convenient communication and scheduling, both domestically and with Vietnam.
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References
- National Institute of Standards and Technology — Time: https://www.nist.gov/pml/time-and-frequency-division
- USA.gov — About the U.S.: https://www.usa.gov/about-the-us
Read more: Overview of the EB-3 visa for US immigration · The United States: Overview of Geography, Population, and Economy


