How Many Time Zones in USA: Standard vs Daylight Savings Time Clock

Discover how many time zones in USA exist and how they impact Indian students. From submitting university applications and scheduling interviews to attending online classes, understanding time differences and Daylight Savings Time and the standard time are crucial skills for calculating America time now to avoid missing deadlines.

Understanding how many time zones in the United States is vital for Indian students planning to study in USA, attend online classes, schedule visa interviews, or travel across America. More than a geography fact, it’s a key survival skill for meeting deadlines, joining webinars, and even booking flights. Understanding how many time zones in USA is essential to identify time in USA, the USA time now and the difference with IST correctly, and navigating Daylight Saving Time can significantly impact academic success.

How Many Time Zones in USA

Officially, time is divided into six time zones in USA based on its mainland geography - Eastern Time (ET), Central Time (CT), Mountain Time (MT), Pacific Time (PT), Alaska Time (AST) and Hawaii – Aleutian Time (HAT). The America time zone is further divided into winter clock and summer clock in a rolling year. The American time zone in winter follows standard time, one hour later, and is also known as daylight saving time or DST. Whereas the summertime clock is one hour ahead of the actual time, usually denoted as standard time or ST.  

US Time Zones at a Glance (Standard vs. Daylight)

Check out the table below showing time zones in USA based on their standard and daylight savings time clock: 

But if you see, officially as per US Department of Transportation, there are nine time zones in USA. Over time, two more time zones have been added to the list - Howland Island and Baker Island (uninhabited regions in USA plus one as anywhere on earth), making it 09 America time zones. Time zones in USA have a different way of reference: 

• Contiguous US time zone - The typical four divisional time zone is divided into the US map.
• Standard time in the USA - The winter clock that is used in USA and a combination of American time zones followed by different states.
• Daylight savings time clock - The summer clock in the US.

Each time zone in USA is denoted differently, read differently and means differently. To calculate USA time now, there is a different formula altogether. We have given everything about how many time zones in USA in the sections below and what each of them mean. It is essential to understand them to get a view of USA time now in real time. 

States and Time Zones in USA

Since different clocks signify different times in USA, there is a sure way of reading it. Indian students usually follow the IST or the Indian Standard Time and may initially have confusion, but once they get the hang of how many time zones in USA exist and how to read them, it will be a cakewalk.

1. Contiguous US Time Zones (PT, MT, CT, ET)

The main geographical country of US is divided into four time zones, comprising 48 states together or connected. These four main time zones in USA are as follows:

The United States time zones in the contiguous US are often referred to by their generic names, without distinction. However, the US is not limited to the connected 48 states only; there are other states in the US which are segregated from the central geographical region and thus, follow a different time zone.

Each time zone has a one-hour gap. So if it is 11:00 a.m. as per Pacific Time, then it will be 12:00 p.m. as per MT, 1:00 p.m. as per CT and 2:00 p.m. as per ET.

2. Standard Time Zones in USA

The standard time zones in USA are basically winter clocks that are followed. That is, the clocks are delayed by one hour when referring to Pacific, Eastern, Central or Mountain times. Their abbreviations usually have ST preceded by P, E, M or C based on the time zones being referred to. So those who want to know what time is USA in as per UTC, know that the Standard Time varies per geographical region. Check out the different standard America time zone and how to calculate them in IST:

PST Time Zone States in USA

PT is commonly also referred to as Pacific Standard Time (PST). PST time zone states in USA are about four, namely - 

1. Washington
2. Oregon
3. Nevada
4. California

Indian students enrolled in any of the universities falling under these states, like the University of California, Stanford, the University of Washington, Seattle University or the University of Oregon, thus follow the PST time zone in USA. Also, they will have to calculate Indian Standard Time (IST) by adding 13 hours and 30 minutes to the current PST.

EST Time Zone States in USA

Similarly. ET is commonly referred to as Eastern Standard Time (EST). EST time zone states in USA are about 17, which fully follow the EST time. Apart from this, there are six US states that partially follow the EST and also follow the Central Standard Time (CST). EST time zone states in USA fully following this timeline are as follows:  

1. Connecticut
2. Delaware
3. Georgia
4. Maine
5. Maryland
6. Massachusetts
7. New Hampshire
8. New Jersey
9. New York
10. North Carolina
11. Ohio
12. Pennsylvania
13. Rhode Island
14. South Carolina
15. Vermont
16. Virgina
17. West Virginia

Indian students studying in any of the above-mentioned US states across universities like Ivy League schools, or Johns Hopkins University, University of South Carolina, University of Delaware, and others can calculate Indian Standard Time as 10 hours and 30 minutes ahead of the current EST. 

CST Time Zone States in USA

CT is commonly referred to as Central Standard Time (CST). CST time zone states in USA include nine states. These are as follows:

1. Minnesota
2. Wisconsin
3. Iowa
4. Illinois
5. Missouri
6. Arkansas
7. Louisiana
8. Mississippi
9. Alabama

For those who wish to calculate IST based on CST time zone states in US can add 10 hours and 30 minutes to the current time to know the time in IST. Indian students enrolling at the University of Wisconsin-Madison, the University of Minnesota-Twin Cities, UIUC, the University of Arkansas, and other institutions should be aware of the CST time zone to convert to IST.  

MST Time Zone States in USA

MT is commonly also referred to as Mountain Standard Time (MST). MST time zone states in USA are around seven states, they are:

1. Montana
2. Idaho
3. Wyoming
4. Utah
5. Colorado
6. Arizona
7. New Mexico

MST time zone states are one hour behind the CST. Thus, to calculate IST, 11 hours and 30 minutes should be added to MST to get the IST. Students who apply to universities in these states like - ASU, University of Montana, University of Colorado Boulder and others will require this conversion. 

US States Split Across Two Time Zones

While it may be difficult to assess how to calculate real-time America time now for states in USA having different time zone combinations. A simple soluion to this problem is by first identifying the states time zones and then calculating the USA time now. Check out the US states that are use a dual time zone: 

These are some of the US states time zones that clash with one another during the standard time clock. 

3. Daylight Savings Time Clock in USA

Daylight Savings Time (DST) in the United States is the practice of advancing clocks by one hour in the spring (“spring forward”) and setting them back by one hour in the fall (“fall back”) to maximise daylight during summer months. It starts on the second Sunday in March and ends on the first Sunday in November.

NOTE: Hawaii and most of Arizona do not observe it, including territories of Puerto Rico, Guam, American Samoa, Northern Mariana Islands and US Virgin Islands.

For students in India, this implies that the time difference between IST and the United States changes twice a year, impacting exam result release timings, online classes, and university deadlines. Let us review the time difference between Coordinated Universal Time (UTC) and the four contiguous US time zones. We will also examine the difference compared to Indian Standard Time (IST), which is UTC +5:30:

1. Eastern Time (ET): Standard time is UTC-5, and as per IST, it is +10:30 hours. Therefore, EDT is UTC-4, and IST falls to +9:30 hours.
2. Central Time (CT): Standard time, as per UTC-6, and as per IST, is 11:30 hours ahead. However, CDT becomes UTC-5, and IST falls to +10:30 hours.
3. Mountain Time (MT): Again, the Mountain Time standard time is UTC-7, which is 12:30 hours ahead of IST. MDT is UTC-6, and IST is 11.5 hours ahead.
4. Pacific Time (PT): Standard UTC -8 and IST is +13:30 hours. But PDT is UTC -7, where IST is +12:30 hours

This is how the daylight saving time clock in the USA works. It is essential to understand the different time zones in USA to ease the application process in USA for international students. However, it may seem tricky and can lead to incorrect conversions; we have provided a table for reference, comparing Daylight Saving Time to IST.  

Daylight Savings Time Clock vs Standard Time into IST

Time difference in USA based on IST can sometimes be tricky because states and time zones in USA differ from one another. Check out the conversions below to understand how to calculate time easily: 

All Time Zones in USA Converted to IST

Since we have noted that there are officially nine United States time zones with two more for unhabited areas, there is one additional time zone as well. However, for Indian students, only nine time zones work. Let us check out how to calculate America time now based on current time based on IST for reference:

Since time in USA is behind the Indian time, to calculate USA time now, applicants can deduct the hours based on IST for the United States time zones they are referring to. The majority of universities, including top universities in the USA, publish application deadlines in various formats based on the time zone in which their institutions are located. This is why it is essential to know the time in USA. 

US Time Zones for Indian Students: Do’s & Don’ts (with IST)

While it is possible to get lost in the whirlwind of time zones in USA, it is equally challenging to decode how to read the USA time now. Here are a few do’s and don’ts for reference not to get wrong when decoding time in America based on daylight savings time clock or standard time in the USA:

Necessity of Understanding America Time Zones for Indian Students 

Every year, millions of international students, including those from India, apply to various US universities for admission. For which they must follow the EST for submitting their applications, exam scores, attending online orientations, and participating in interviews. The different time zones in USA plays a significant role because of the following reasons:

• Joining lectures often means calculating the difference between IST and the America time zones. There can also be confusion between EST and EDT. 
• Deadlines for some standardised exams, such as the SAT exam, typically have their final registration deadlines at 11:59 p.m. ET, which is 9:29 a.m. IST.
• Then, test scores of standardised tests, such as the SAT exam, are released around 8:00 a.m. ET, which is 5:30 p.m. IST. Therefore, even if there is no notification from the College Board, Indian students typically know that they can access their SAT scores by that time.
• US university portals may close at midnight local time for admissions, which could be in the morning or afternoon in India.
• The student visa in USA and also the university interviews use local US time references, so converting accurately is critical.
• When travelling from India to study in USA, it is again essential to know the United States time zones so that students land at a decent time and face no issues when travelling to their student accommodations.

Missing America time zone conversion can result in lost opportunities, late submissions, or even missing key orientation meetings. Planning saves stress and builds professionalism.

So, to answer how many time zones in USA, four would be incorrect, because ideally there are nine! And of course, there are additional add-ons. Indian students should identify the US state to which they are applying and then understand how the standard time or daylight savings time clock works to calculate real time or USA time now.