AST – Atlantic Standard Time


Understanding time zones and time zone differences is key in this day and age where we often work, socialize, and connect with people around the globe. At a first glance, time zones may appear confusing, especially when you throw daylight savings time into the mix. However, there’s a simple hack to figure out time zones and different time around the world quickly, and it all starts with the concept of…sunrise. 

Intrigued? Be sure to keep reading to find out an easy way to calculate time differences around the globe quickly, learn about the Atlantic Standard Time – the AST time zone that covers over 25 countries worldwide – and find some fun facts at the end of the article to keep you entertained while you work out the global time.

Time Zones Explained

Here’s the thing: the Earth is a rotating sphere (sorry, flat earthers), and that means that the rising sun hits different parts of the globe at different times. In other words, when it’s dawn in LA, it’s already dusk in Paris – that’s because as the Earth rotates around the sun, different parts of it are exposed to daylight.

So if it’s dawn in LA and dusk in Paris, what’s the time in the US and what’s the time in France? It can’t be the same – and that’s where time zones come in. In 1878, a Scottish engineer, Sir Sanford Fleming, proposed a simple way to measure time around the globe: since the Earth rotates fifteen degrees every hour (that is, 360 degrees in 24 hours), it makes sense to divide the world into twenty-four time zones, each 15 degrees of longitude apart.

Now, the starting point of measuring time zones is the Greenwich Meridian, or longitude zero. Going West from here, you’ll need to subtract hours, and going East, add them: in other words, if it’s West of Greenwich, it will have a negative time difference (going “backwards”), and if it’s East, it’ll be “going forward”. For example, Madrid is GMT -2, whereas Moscow is GMT +3. Looking at time zones this way, you can easily calculate time differences by subtracting or adding hours depending on the geographical location.

There’s just one kicker: GMT is no longer a time standard. Wait, what? While GMT remains a time zone, since 1972, Coordinated Universal Time (UTC) became the world’s time standard. This is for the sake of accuracy – the GMT cannot be used as a time standard because of tiny, atomic discrepancies in the Earth’s rotation (it may take a few seconds slower or faster from year to year). To avoid these discrepancies, UTC is calculated by highly accurate atomic clocks, and for decades now, UTC has been used as the time standard around the globe. And so, when calculating time differences, you’ve got to look at the UTC rather than GMT offset.

So how does it all work in real life? Let’s take a closer look at one of the time zones – the Atlantic Standard Time – to figure it out.

What is Atlantic Standard Time

Atlantic standard Time, as the name suggests, covers the area along the Atlantic coast – namely, the easternmost parts of Canada, the US, the Caribbean, and parts of South America. Atlantic Standard Time is four hours behind UTC, that is, it’s UTC-4. The interesting thing is, while it covers large parts of the US and Canada, it’s only used in Newfoundland and Labrador and, when it comes to the US, Puerto Rico and the Virgin Islands.

To make matters even more confusing, the Atlantic Standard Time is only observed between the first Sunday in November and the second Sunday in March. During the summer and fall months, it cedes to the Atlantic Daylight Saving Time (ADT).

And to top it all off, several New England states in the US are considering shifting to the Atlantic Standard Time as the new norm. In 2017, there was a proposal that shifting to the Atlantic Standard Time (year-round, with no changes to daylight savings) would be highly beneficial; Florida, at the same time, is aiming for the “Sunshine Protection Act” where the state would observe the Eastern Daylight Time – equivalent to the Atlantic Standard Time – year round, to keep those sun-drenched hours as long as possible daily. These changes may take a while – they can only take effect when it’s passed into federal law by the US Congress – but the Atlantic Standard Time clearly has fans all the way from New York to Miami.

Countries in Atlantic Standard Time

Whether they observe the Atlantic Standard Time or not, and whether daylight savings time changes apply or not, the AST covers a large area. Countries covered by the Atlantic Standard Time include:

  • Antigua and Barbuda 
  • Barbados 
  • Brazil, in the following areas: Amazonas, Mato Grosso, Mato Grosso do Sul, Rondônia, Roraima 
  • Bolivia 
  • Canada, in the following areas: Nova Scotia, New Brunswick, Prince Edward Island, Most of Labrador, Magdalen Islands, Quebec,Côte-Nord 
  • Chile (except Magallanes region and Antarctic territory)
  • Dominica 
  • Dominican Republic 
  • France and French overseas territories, in the following areas: Guadeloupe, Martinique, Saint Barthélemy, Saint-Martin 
  • Greenland, in the following area: Thule Air Base, Grenada, Guyana 
  • Netherlands and Dutch special municipalities, in the following areas: Aruba, Bonaire, Curaçao, Saba, Sint Eustatius, Sint Maarten 
  • Paraguay
  • Saint Kitts and Nevis 
  • Saint Lucia 
  • Saint Vincent and the Grenadines 
  • Trinidad and Tobago 
  • United Kingdom (British Overseas Territories), in the following areas: Anguilla, Bermuda, British Virgin Islands, Montserrat (no DST)
  • United States, in the following areas: Puerto Rico, United States Virgin Islands 
  • Venezuela (no DST)

Interesting Time Zone Facts

If your head is already spinning trying to figure out time zones, places where the Atlantic Standard Time is observed, and differences in time around the world, it’s time to delve into the fun part of the AST time zone explanations: some fun facts about time zones worldwide! Here’s a list of our favourites:

  • Newfoundland kind of observes the Atlantic Standard Time… but it also kind of observes the UTC-3 time zone, resulting in the island having its very own offset – half an hour. This is because it sits right smack in the middle of both time zones, so, being practical, the Newfoundlanders found a way to appease both sides.
  • Speaking of quirky time zone decisions, China tops all charts: in 1949, China has standardized all of its time zones to Beijing time. Having in mind how vast the country is, it’s hard to imagine how it’s 7am in Beijing and 7am in Xinjiang at the same time despite a 2,000-mile distance, but who are we to argue – time, after all, is relative. China’s closest neighbours such as Pakistan may beg to differ, though – because of China’s one time zone policy, there’s a three-hour difference between China and Pakistan right across the border. As soon as you cross it, you’ll need to turn your clock backward of forward three hours, even if the crossing itself took a few minutes.
  • While China’s timekeeping decisions may sound a tad odd, France isn’t far behind: it’s the only country in the world where, officially, the sun never sets thanks to France’s remaining territories around the globe. Louis XIV would be pleased.
  • Much like Newfoundland, not all countries around the world follow the standard UTC offset of an hour. Ever-original, India uses an offset of five and a half hours, and Nepal has decided to observe UTC +05:45, so if you’re traveling to the Himalayas, get your minutes right!
  • Ever felt nostalgic about “Yesterday”, the famous hit song by John Lennon? Thanks to time zones, you can actually travel to…yesterday. You can depart from, say, Rome at 7am Monday morning and find yourself back on Sunday in San Francisco. We’re all for longer weekends, if you ask us.
  • Time travel can also be fun: if you feel like celebrating Christmas, New Year’s Eve, or your birthday multiple times a day, just book a ticket flying West, wind the clock back, and keep on partying!
  • On the other hand, hopping across time zones can be exhausting – jetlag is a price you pay traveling long distances, whether you’re heading West or East. Curiously enough, it’s Eastward travel that drains the energy the most as it extends the day forcing our bodies to stay awake and alert longer. Traveling West, your day s actually shortened, so your body can catch up on some rest. Pro tip? If jetlag is a constant struggle, power nap while in the air – short periods of zzz can help you adjust to a different time zone faster.

So thee you have it: whether you live in an area that observes the Atlantic Standard Time or perhaps often work or communicate with people who do, you now know how to calculate the time difference and stay on top of your scheduling game at all times (pun intended).