The first day of spring in the Northern Hemisphere is marked by the Spring Equinox, also known as Vernal or March Equinox, that occurs on one of the dates among 19, 20 or 21st March. The first day of spring in 2018 fell on March 20, 2018, at 12:15 pm (Eastern Time or ET).

Equinox is a moment when the sun gives out equal sunlight to both northern and southern hemispheres. In other words, day and night are of almost same length in hours.

In fact, equinoxes occur one day, twice a year on every planet of the solar system, including earth. These two equinoxes are marked as vernal equinox and autumnal equinox.

In the earth’s northern hemisphere, the vernal equinox cues the first day of spring in the March month. The Equinox is determined through two ways as a meteorological cycle, and the other is astronomical. We will see both later in this article.

When is the first day of spring 2017, 2018, 2019, 2020?

The following are the date and time when the first day of spring has fallen and will fall:

  • 2017 – March 20, Monday @ 6:28 am ET
  • 2018 – March 20, Tuesday @ 12:15 pm ET
  • 2019 – March 20, Wednesday @ 05:58 pm ET
  • 2020 – March 19, Friday @ 11:50 pm ET

What is an Equinox?

Equinox is a time when the sun rays fall precisely perpendicular to the earth’s equator. This enables the sunlight to fall equally in the northern and southern hemispheres.

The other way of understanding is that the during the equinox, the virtual line dividing daytime and nighttime passes through earth’s north and south poles.

Change of seasons can be represented by the four different positions of earth on the elliptical orbit around the sun. These four positions are –

Equinox Explanation with representation

Winter solstice (Around 22nd December)

Winter solstice indicates the beginning of winter in the northern hemisphere. Sun rays fall perpendicular to earth’s surface. Since Earth always remains titled at an angle of 23.5 degrees, so the rays fall at an angle with the celestial equator.

Sun rays fall at the tropic of Capricorn, which is more to the southern hemisphere.

Vernal Equinox (Around 20th March)

Vernal equinox or March equinox indicates the first day of spring. Now as the earth revolves around the sun on the elliptical path, the sun rays also shift south to north crossing the celestial equator. The Earth reaches a point where the equator falls almost perpendicular to the sunrays.

At this point, both north and south hemispheres receive an equal amount of sunlight. It is also said that on this day, the sun rises and sets precisely in the east and west respectively.

Summer solstice (Around 23rd June)

Summer solstice indicates the beginning of summer in the northern hemisphere. It comes almost after six months from winter solstice or 3 months after the vernal equinox.

Sun rays fall at Tropic of Cancer, which is more to the northern hemisphere and above the equator. Here also, sunlight falls at an angle with the celestial equator.

Autumnal equinox (Around 23rd September)

Soon after the summer solstice, sunlight will shift further as the earth is revolving. A point is again reached where the sun rays are precisely perpendicular to the equator.

Here also, day and night hours are almost equal. Autumnal or fall equinox indicates the first day of fall in the northern hemisphere.

How do you fathom when the First Day of Spring will take place?

  1. The meteorological cycle: Meteorologists follow this cycle which uses the temperature and weather to determine the first day of spring. According to the meteorological cycle, the First day of Spring in 2018 fell on the 1st of March
  2. The Astronomical cycle: This method is used by climatologists and also the whole world and is calculated regarding the Earth’s position in accordance to the Sun. According to the Astronomical cycle, the first day of Spring in 2018 fell on the 20th of March

Ancient buildings that mark the spring and Autumn Equinox

  1. El Castillo in Chichen Itza: This is the most famous building built during 1000 AD in the Mayan ruins, currently Mexico. This building was an ode to Kukulkan, the serpent God.
    During the sunset of the equinoxes, the light hits a perfect angle and makes the shadow of a snake, making its way down the stairs of the massive pyramid. Thousands of people visit this temple to see the beautiful sight during the equinoxes.
  2. The Stonehenge: More than a thousand people visit the Stonehenge every year to see the Sun as it alights with the huge and ancient rocks.
    The Stonehenge is one of the most famous English Heritage and opens early at dawn so that tourists and citizens can see the wonder of nature.
  3. Machu Picchu at Peru: The beautiful Machu Picchu at Peru is almost invisible to the eye from below as they are built up in the mountains. But at midday on the day of the equinoxes, the sun hits the Intihuatana Stone directly and no shadow.
    Interesting myth: If you touch your forehead to the stone, it is said to give you a look into another world.
  4. The Great Sphinx: On the morning of the Spring Equinox, the Great Sphinx in Egypt is at a position where it is looking or facing directly into the Sun.

Some other famous buildings are Angkor Wat in Cambodia, Mnajdra in Malta, The Great Pyramid of Giza and Tikal in Guatemala.

When is the last day of spring observed?

Just like the first day of spring, the date of the last day of spring is also split due to the two different cycles that prevail.

  1. According to the meteorological cycle, the last day of spring will fall on the 31st of May in 2018
  2. According to the astronomical cycle, the last day of spring will be observed on the 21st of June in 2018

Facts about the Spring Equinox

  1. As the sun moves towards the North, so do the birds. They fly along the path of the Sun
  2. March is also almost the perfect time for planting many plants in some places
  3. Worms are also said to start coming out from the Earth
  4. The Spring Equinox is also the determiner of Easter

Why date around the first day of spring varies?

Vernal equinox falls on three different dates as 19th, 20th or 21st March. Why? The reason is simple as earth does always complete revolution of the sun in 365 days. Sometimes, it does take 366 days (in case of leap year).

Over to you on the first day of spring

During the ancient times, many buildings such as the El Castillo and Stonehenge were built to mark Equinoxes. During the equinoxes, these old structures indicate through signs that are worth watching.

Also, nature also marks the first day of spring or arrival of spring through the blooming of flowers, coming out of the earthworms and flying of the birds along the path of the Sun.

People all over the Northern Hemisphere look forward to the arrival of the beautiful spring and the beautiful environmental changes it brings along.