EDT – Eastern Daylight Time


Many people don’t understand the concept of a time zone. They don’t know much about the different time zones in the world. Of course, everyone knows what time zone they are in. However, how much do you know about time zone differences, and how did scientists come up with time zones in the first place? And, where does the EDT – Eastern Daylight – time zone stand in all of this?

The reality is that time zones are extremely important to everyone, whether we realize it or not. They greatly influence social and commercial activity and have an influence over military communications and operations. Just think about it: if you are based in, say, London, Paris, or Madrid, but you work or communicate with someone who lives in a city that observes the Eastern Daylight Time, you’ll need to know exactly what time is it over there to make sure you don’t call the other person at odd hours.

So, let’s take a look at what the EDT time zone is and how it relates to the other time zones on Earth. In addition, we will list the most important countries and the major cities that are in EDT to make it easier. Curious fact: it is important to note that these countries and cities are not in the EDT time zone all year round, because some of them observe Daylight Saving Time, which means they enter another time zone during the summer months. It may sound confusing at first, but understanding how time zones work and when do countries switch to Daylight Saving Time makes it easier to figure out. And top it all off, you’ll also find a list of fun facts about time zones towards the end of this article.

What Exactly Is a Time Zone?

First things first: you are probably wondering what a time zone really is. Let’s explain it in simple terms. You are probably aware that not all countries on Earth observe noon at the same time. It would be impossible because the Earth is a rotating sphere, and only half of it faces the Sun during the day. Because the Earth rotates, various countries observe noon at different hours throughout the day. 

To coordinate a time and to help people, industries, governments, and businesses, the Earth was split into 24 time zones. The ideal situation is to have the sun at its highest point in the sky when it is noon, that is when crossing the meridian. If we have just one time zone, it would not be possible because the Earth rotates 15 degrees every hour. It was then agreed that a system of multiple time zones be adopted. In this system, the world is divided into 24 15-degree sections and clocks are set according to each time zone, with each time zone having a difference of one hour to the next zone. This will make all the people within a particular time zone set their clock the same way.

For instance, in the United States, there are four time zones. They include the Eastern, Central, Mountain, and Pacific. To have an idea of how they are related: when it is noon in the Eastern time zone, it is 11 a.m. in the Central time zone, 10 a.m. in the Mountain time zone and 9 a.m. in the Pacific time zone. It is important to note that all time zones are measured from a starting point centered at England’s Greenwich Observatory. This point is known as the Greenwich Meridian or Prime Meridian. The time at the Greenwich Meridian is known as Greenwich Mean Time (GMT). The Eastern time zone in the United States is designated GMT-5. This means that when it is noon in the Eastern time zone, then the time is 5 p.m. at the Greenwich Observatory. 

All countries and cities in a time zone observe the same time. There is no difference in time, even if the countries are thousands of miles apart. Different parts of the world enter and exit daylight at different times, so splitting the world into 24 time zones makes a lot of sense. It’s like grouping areas that are in daylight together. 

All time zones are now regulated after Coordinated Universal Time (UTC), which in 1972 became the world’s time standard replacing the GMT. Although the GMT is not considered a standard anymore, it still belongs to one of the 24 time zones of the world. The GMT is especially used by many African countries, in the UK (winter season) and in Western Europe.

The Coordinated Universal Time (UTC) is so-called since it has become the standard by which all the time zones are based. And contrary to what is generally believed, UTC is not a time zone. It is the standard by which all the world timing systems have adopted, synchronizing their local clocks with it. The various time zones are simply designated by the hourly difference between UTC.

The UTC time standard has two main components: the International Atomic Time (TAI) and Universal Time (UTI). TAI is a scale that helps determine the speed at which clocks should tick. It is found by combining the time of more than 200 atomic clocks located worldwide. It is very accurate. On the other hand, UTI is determined by the Earth’s rotation. This is why it is sometimes called astronomical or solar time. Often, timekeepers use to measure the length of a single day on the planet using the UTI.

Because of the International Atomic Time (TAI) and the Universal Time (UTI), Coordinated Universal Time is used to synchronize clocks across the various countries all over the world, and across 24 different time zones.

What is EDT?

So what does that have to do with EDT specifically?

Now that you know exactly how time zones work, it’s time to take a closer look at the Eastern Daylight Time zone. This one is a curious one because it isn’t static: regions in this time zone switch to another one when it’s time to move clocks forward or backward to Daylight Savings. Curiously, EDT isn’t just observed in North America: if you drew a vertical line down from Connecticut, you’d notice EDT also covers parts of Central and South America.

Brief History of EDT

Before we discuss the history of Eastern Daylight Time, it’s important to say a few words about the origins of Eastern Standard Time (EST). Observing EST goes back to the 19th century and is connected with the need for the trains to have standardized time. The first country that started using EST was Great Britain. The country started using EST on December 1, 1847, in the railway system. However, the majority of British public clocks observed GMT until 1855. 

A few decades later, on November 18, 1883, the United States followed Great Britain and started using a standard time in the railroad system. It included not only Eastern Standard Time, but also Central, Mountain, and Pacific. On November 18, 1883, America’s railroads began using a standard time system involving four time zones, Eastern, Central (CDT), Mountain (MST), and Pacific (PCT).

However, the United States began observing Daylight Saving Time for the Eastern time zone much earlier. Specifically, DST was introduced in 1966 by the Uniform Time Act. But the country started saving daylight time only in 1987. 

Unlike DST, Eastern Daylight Time doesn’t have a long history. In fact, daylight saving time was extended to other U.S. time zones in 2005 by the Energy Policy Act, and observing EDT started in 2007. Since then, the states and cities that observe Eastern Standard Time (EST) change their clocks from 2 a.m. to 3 a.m. on the second Sunday in March and return from 2 a.m. to 1 a.m. on the first Sunday in November. That’s the period when EDT is used. 

How Does EDT Work?

Understanding the mechanism of EDT is nothing difficult for those who are aware of the purpose of Daylight Saving Time. Just like Mountain Daylight Time (MDT) or Central Daylight Time (CDT), Eastern Daylight Time (EDT) is used only throughout a certain period of the year. EDT is observed by the countries and states that normally use Eastern Standard Time. It’s the easternmost time zone in the United States and the second Easternmost time zone in Canada.

Specifically, EST is observed by 23 US states, three provinces of Canada, and the Caribbean. All these territories change their clocks by one hour in order to save daylight. In the North American time zone, the use of EDT starts from the second Sunday in March and continues until the first Sunday in November. During the remaining months, these territories use EST. 

Therefore, both EST and EDT make up Eastern Time (ET) together. 

The exact way how EDT works is the following: in order to observe “Summer Time” or DST territories that usually use EST change their clocks on the second Sunday in March, at 2 a.m. and advance them to 3 a.m. This one-hour “gap” is returned back to normal on the first Sunday in November, at 2 a.m. when the clocks are changed to 1 a.m. That’s the entire philosophy of EDT, as easy as that! 

How to Convert EDT to Other Time Zones?

When it comes to time zones, getting to know how to convert one time zone to another is one of the most frequent issues especially for travelers. If you travel across various time zones, you need to prepare your body for the confusing feeling of jetlag and set your plans properly. Understanding the difference between time zones is the easiest way for this. 

So, if your country or the destination country is in the process of observing daylight time and you want to convert Eastern Daylight Time to other time zones, pay attention to the list below:

  • EDT is 1 hour ahead of Central Daylight Time (CST).
  • EDT is  2 hours ahead of Mountain Daylight Time (MDT).
  • EDT is 3 hours ahead of Pacific Daylight Time (PDT).

Consequently, in order to convert EDT to CDT, you need to discount one hour; In order to convert EDT to MDT you need to discount two hours, and in order to convert EDT to PDT you need to discount three hours. 
But if you still feel confused about the time conversation, just go ahead and use online resources like worldclock.com and avoid the rather puzzling process of determining the exact time of the destination country.

Major Countries in EDT Time Zone

Now that you know what a time zone is, what EDT is, and how it related to Coordinated Universal Time, we also need to cover the seasonal Daylight Saving Time changes.

Daylight Saving Time is the system of setting the clocks forward one hour from standard time (the local time in a country or region when daylight saving is not in use) during the summer months and back again in the fall. This is to ensure better use of natural daylight. Established in the early twentieth century, the system of daylight saving is now widespread over 70 countries worldwide, but whether a country observes DST or not is its own choice. Unlike time zones, Daylight Savings is something countries agree on, rather than a universal global standard. Some countries adhere to seasonal DST changes, others do not, and others still (Australia, for example) have different regions which observe or ignore the DST on their own.

Understanding DST is important when talking about EDT because Eastern Daylight Time is directly affected by DST. What this means is, whenever you’re trying to reach someone in, say, Florida, don’t just check what the current time in EDT is – keep in mind it may be an hour ahead or behind depending on the season.

Now, it’s time to take a look at the major countries that are in the EDT time zone. The following states in North America are in the EDT time zone:

  • Connecticut
  • Delaware
  • District of Columbia
  • Florida – Southern/Eastern parts Show
  • Georgia
  • Almost all of Indiana
  • Kentucky
  • Maine
  • Maryland
  • Massachusetts
  • Michigan – most except these western counties Show
  • New Hampshire
  • New Jersey
  • New York
  • North Carolina
  • Ohio
  • Pennsylvania
  • Rhode Island
  • South Carolina
  • Tennessee – eastern counties Show
  • Vermont
  • Virginia
  • West Virginia

There are also three Canadian territories that are in the EDT time zone during the summer months: Nunavut, Ontario and Quebec. Also, there are two Caribbean territories that are in the EDT time zone in the summer months: Bahamas and Haiti. In South America, we have Colombia, Ecuador, Peru and some parts of Brazil. Other countries that are in the EDT time zone during parts of the year include Mexico, Panama, Jamaica, Haiti, and Cuba. As you can notice, there are a lot of relatively large territories in this time zone. Although there are no exact figures, the number of people living in the Eastern Daylight Time zone is in the hundreds of millions. And yes, all of these people are observing the exact same time, which is UTC-04:00. There is no difference in time between New York and Cuba!

Major Cities in the EDT Time Zone

Because Eastern Daylight Time covers such a large area, it is only natural to have a lot of major metropolitan areas in it. Here are some of the largest cities in the EDT time zone:

  • Washington, D.C.
  • Atlanta, Georgia
  • Baltimore, Maryland
  • Barrie, Ontario
  • Bogotá, Colombia
  • Boston, Massachusetts
  • Burlington, Vermont
  • Charleston, West Virginia
  • Charlotte, North Carolina
  • Cincinnati, Ohio
  • Cleveland, Ohio
  • Columbia, South Carolina
  • Columbus, Ohio
  • Detroit, Michigan
  • Grand Rapids, Michigan
  • Greater Sudbury, Ontario
  • Guayaquil, Ecuador
  • Hamilton, Ontario
  • Havana, Cuba
  • Indianapolis, Indiana
  • Iqaluit, Nunavut
  • Jacksonville, Florida
  • Kingston, Jamaica
  • Knoxville, Tennessee
  • La Paz, Bolivia
  • Lima, Peru
  • London, Ontario
  • Louisville, Kentucky
  • Manchester, New Hampshire
  • Medellín, Colombia
  • Miami, Florida
  • Montreal, Quebec
  • Nassau, Bahamas
  • New York, New York
  • Orlando, Florida
  • Oshawa, Ontario
  • Panama City, Panama
  • Philadelphia, Pennsylvania
  • Port-au-Prince, Haiti
  • Portland, Maine
  • Quebec, Quebec
  • Quito, Ecuador
  • Richmond, Virginia
  • Rochester, New York
  • Springfield, Massachusetts
  • Thunder Bay, Ontario
  • Toledo, Ohio
  • Toronto, Ontario
  • Trenton, New Jersey
  • Wilmington, Delaware
  • Windsor, Ontario
  • Worcester, Massachusetts

Difference Between EDT and EST

People often get confused by the similarities of EDT and EST because they only differ by one letter. The most obvious thing about these two time zones is that both of them represent Eastern Time (ET). But what’s the difference between EDT and EST?

Let’s start with EST. It’s short for Eastern Standard Time, a time zone that is used when observing standard time and is five hours behind Coordinated Universal Time. Therefore, EST is UTC – 5 hours. This time is usually used by North Americas in the fall and in winter.

As we already pointed out, EDT is an abbreviation of Eastern Daylight Time. It’s used by North American territories that observe daylight saving time.  EDT is four hours behind Coordinated Universal Time (UTC – 4 hours). Usually, EDT is used during the spring and summer which is why it’s also called “Summer Time”. 

So, here are the main points about EDT vs EST:

  • EDT and EST are time zones under the Eastern Time Zone (ET).
  • Both EDT and EST are used in the 21 North American time zones, including 9 time zones in the USA including Alaska and Hawaii, and 4 standard time zones in the mainland. 
  • EST is 5 hours behind the Coordinated Universal Time and EDT is four hours behind. So, EST is UTC-5, EDT is UTC-4. 
  • Both EDT and EST are used in the same areas of the United States and Canada but in different seasons. Specifically, EST is used during fall and winter, while EDT is used in the spring and summer. 

Now you probably acknowledge the power of Daylight Saving Time on various time zones and hopefully, when it comes to the differences between EST and EDT, you won’t get confused anymore!  

Fun Facts About Time Zones

Now that you know what the EDT time zone is, how it relates to Coordinated Universal Time (UTC) and what countries and cities it covers, let’s take a look at some of the most interesting and fun facts about time zones:

  • UTC time coordinates time in all time zones; this is why the UTC offset was created. However, UTC is being periodically adjusted itself using leap seconds, because the slowing rotation rate of the Earth is making UTC drift away from atomic clock time every year.
  • Emails coming from a sender who is in the EDT time zone will have the -0400 email time zone indicator in their headers. However, the sender may not be in EDT time because there are other time zones that use the UTC-04:00 offset during some parts of the year.
  • EDT is a daylight savings time, so it used only during summer months. The rest of the year, the time zone is Eastern Standard Time (EST), which is UTC-05:00. Keep that in mind when trying to call someone who lives in New York!
  • GMT is the time zone that follows UTC time (it has no UTC offset). However, GMT is GMT+01:00 during summer months in most parts of the time zone. This happens because the United Kingdom observes Daylight Savings Time.
  • Daylight savings time is both an ancient and a recent invention. Historical records show that romans observed changes in daylight during the summer months and adjusted their water clocks accordingly; in recent history, ideas about daylight saving time started appearing in the nineteenth century and were finally materialized in the early 1920’s due to Germany’s effort to save energy during the war. Eventually, moving the clocks forward and back to enjoy more daylight during the summer days became the norm in most Western countries.
  • Although Daylight Saving Time is observed in over 70 countries around the world, not everyone is happy about it. In Europe, surveys show most Europeans would like to ditch DST altogether, and in the United States, there is a movement called Lock the Clock lobbying for abolishing the seasonal DST changes.
  • Perhaps unsurprisingly, not all countries observe Daylight Savings Time. Examples include most of Africa, Argentina, Peru, and even parts of Australia.
  • Countries who are on or close to the equator don’t need to observe Daylight Saving Time because around the Earth’s circumference, the days and nights are always 12 hours long and there are no seasonal changes in the length of daylight hours or darkness. Way to go, Ecuador!
  • India has a single national time, which is UTC+05:30. And no, not all countries use whole hours for their UTC offset. Nepal even went as far as to use a time that is UTC+05:45.
  • Hawaii never changed its time from UTC-10:00 (it doesn’t observe DST). The fun fact is that Hawaii is in the same time zone as Alaska in the winter months.
  • The date of December 30, 2011 did not exist for Samoan residents. On that day, the country skipped a whole day when it moved time zones.

So there you have it: with time zones and the brief history of time explained, you’ll never mix your time zones up again or mistake EDT for a static time zone – remember, while not everyone may be happy about it, DST still affects the Eastern Daylight Time zone, so keep that in mind when reaching out to your friends in Florida or Vermont!