What is the Spring Equinox?

From an Eastern perspective, the spring equinox marks the middle of spring. 

Learn about the Spring Equinox.

According to the ancient Chinese agricultural calendar, each year has 24 solar terms, corresponding to 24 periods of change in the natural world. The spring equinox is one of these 24 solar terms. "Spring" refers to the spring season in the four seasons of spring, summer, autumn, and winter; "equivalence" means the middle. Thus, the spring equinox can be simply understood as the middle point of spring according to the agricultural (lunar) calendar .

The vernal equinox is also considered a special day in the Western Gregorian calendar. However, unlike the vernal equinox in the Eastern concept, which marks the middle of spring, the vernal equinox is seen by Westerners as the beginning of spring in the Northern Hemisphere, the time when the Sun appears on the "celestial equator" (the Sun is closest to the equator) and moves northward.

The vernal equinox is the day when daylight and nighttime are equal in length at the equator. According to Western science, this marks the beginning of spring in the northern hemisphere or the beginning of autumn in the southern hemisphere.

In the Southern Hemisphere, this day is the Autumn Equinox. On this day, the sun rises from the horizon precisely in the east and sets from the horizon precisely in the west. Additionally, the sun is directly overhead at noon.

The spring equinox is celebrated as a holiday in many parts of the world.

The Iranian festival of Norouz (New Year or Spring Festival) is celebrated on this day. The Bahai faith calls it Naw-Rúz. There is also the Ostara festival of Wicca, and it is one of the eight Sabbat festivals of neopaganism.

In Japan, the Spring Equinox (春分の日) is an official national holiday for people to visit ancestral graves and reunite with their families.

Easter in Christian countries is celebrated on the first Sunday after the full moon following the Spring Equinox.

Around this time, the Lao New Year, Thai New Year, and Burmese New Year also begin to be celebrated in mid-April. Mid-March also marks the beginning of Nisan, the first month of the Jewish religious calendar. The Tamil New Year of South India, celebrated after the spring equinox, is called Tamil Nadu.

Earth Day has been celebrated annually on the spring equinox since its first date, March 21, 1970.

Experience the spring equinox from nature and the earth.

Because Earth's orbit isn't vertical, but tilted 23 degrees relative to the ecliptic plane, some areas in the hemisphere receive more sunlight than others. On the two equinoxes of the year, the Earth is directly facing the Sun, so day and night are of equal length. However, since Earth is constantly moving, this equality will quickly be disrupted.

It's easy to see that sunny, breezy weather and the sweltering heat of summer are approaching in the northern hemisphere. Additionally, if you live in the polar regions of the northern hemisphere, you'll see the sun rising from the eastern horizon in the next few weeks. Days will gradually get longer, the weather will be warmer, and you won't need a jacket anymore. You'll also notice the sun's path across the sky gradually shifting northward throughout the day.

During the spring equinox, plants and animals flourish and reproduce.

The spring equinox marks the flourishing and reproduction of plants and animals, accompanied by spring thunder and refreshing spring rains that nourish the fields. Air temperatures rise and stabilize, dispelling the cold. An ancient saying goes, "The spring equinox awakens the veins, a moment is worth a thousand gold ," meaning this is the best time to sow and prepare for the harvest.

During the Spring Equinox, the most notable spiritual and ceremonial activity is the Qingming Festival, a time for visiting and cleaning ancestral graves. On this spring day, descendants prepare offerings to visit and clean the graves of their ancestors to show filial piety and to promptly repair any damaged or deteriorated parts.

During this period, yin and yang are in balance, the weather is favorable, all things flourish, and the length of day and night is equal, hence the name Spring Equinox, meaning the spring season is divided equally. Ancient people considered the period from the beginning of spring to the beginning of summer as spring, with the Spring Equinox being the middle of that time, when the spring energy is at its peak.

The spring equinox is not only auspicious for farming and planting, but it is also particularly beneficial for weddings, pregnancies, and childbirth, promising good fortune and well-being. Therefore, fortune tellers often advise holding joyous events during the spring equinox.

Spring Equinox in Vietnam

The Spring Equinox in Vietnam isn't particularly special. However, many places around the world celebrate it as a holiday. Christian Easter is the first Sunday after the full moon following the Spring Equinox. In Japan, the Spring Equinox (春分の日) is a national holiday for visiting ancestral graves and family reunions, followed by Qingming Festival on April 4th.

On the spring equinox, the sun moves northward; on the autumn equinox, the sun moves southward. (illustration).

The equinox occurs twice a year, once in the spring, known as the vernal equinox in March, and again in the autumn, known as the autumnal equinox in September. On the vernal equinox, the sun moves northward, and on the autumnal equinox, the sun moves southward. The position of the sun at the vernal equinox is used to determine the zero point of both right ascension and declination.

But in reality, these things aren't entirely accurate, due to a phenomenon called equinox precession. Over hundreds of years, the Earth's rotation around its axis in space changes as it acts like a gyroscope. This means the position of the equinoxes moves across the sky at a rate of 50 arcseconds per year.

Spring equinox according to meteorology

When it is spring in the Northern Hemisphere, it is autumn in the Southern Hemisphere, and vice versa. During the spring (or vernal) equinox, days and nights are approximately twelve hours long, with day length increasing and night length decreasing as the season progresses.

Subtropical and tropical regions have climates that are better described in terms of the seasons, for example, dry or wet, monsoon or cyclonic. Cultures may have local names for the seasons that are less equivalent to terms originating in Europe.

Different cultures may have local names for the seasons that have little equivalent to terms originating from Europe. (illustrative image)

Meteorologists typically define four seasons in many climates: spring, summer, autumn, and winter. These are delineated by their average monthly temperature values, with each season lasting three months.

The three warmest months are summer, the three coldest months are winter, and the in between are spring and autumn. Spring, when defined in this way, can begin on different dates in different regions.

Another name for the March full moon is the Sap full moon, because this is the time of year when the sap of sugar maple trees begins to flow.

Therefore, in the US and UK, the spring months are March, April, and May, while in New Zealand and Australia, spring usually begins on September 1st and ends on November 30th.

Swedish meteorologists define the beginning of spring as the first time that the average daytime temperature exceeds 0 degrees Celsius for seven consecutive days, thus the days vary with latitude and altitude.

There has been a change in concept for astronomers.

In some Northern Hemisphere cultures , for example in Germany, the astronomical equinox, which shifts from March 19th to 21st, is taken to mark the first day of spring, and the summer solstice, around June 21st, is taken as the first day of summer.

In Persian culture , the first day of spring is the first day of the first month (called Farvardin), which begins on March 20th or 21st. In other traditions, this day is chosen to be in the middle of spring.

In the traditional Chinese calendar , the "spring" (春) seasons encompass the period between the beginning of spring (March-May), with the spring equinox (February 20-22) as its midpoint, and then ending at Lixia (May-July).

Similarly, following Celtic tradition , which relied solely on daylight and the power of the midday sun, spring began in early February and continued until early May.

The beginning of spring is not always determined by a fixed date on the Gregorian calendar.

Spring is associated with biological indicators such as the blooming of a variety of plant species, animal activity, and the distinctive smell of soil that has reached a temperature conducive to microbial growth.

These indicators, along with the onset of spring, vary according to local climate and the specific weather of a particular year. Most ecologists divide the year into six seasons without fixed dates.

Beyond spring, ecological calculations define a separation prior to the prevernal (early or before spring) season between the hibernal (winter) and vernal (spring) seasons.

This is the time when only the hardest-flowering plants, like crocuses, are in full bloom, sometimes while a few snowflakes still remain on the ground.

In early spring, the Earth's axis is tilting more sharply toward the sun, and the length of daylight increases rapidly for the relevant hemisphere. The hemisphere begins to warm up considerably, causing new plant growth to "sprout," giving the season its name.

The Spring Equinox in 2024 will be on Wednesday, March 20, 2024. 

The 2024 Spring Equinox occurred precisely at 10:06 AM.

The weather during the spring equinox is warmer, so there's no need to wear a jacket when going outside. However, this is a transitional period between cold and hot climates. The elderly and children need to be especially careful to prevent respiratory illnesses and ear, nose, and throat problems. Additionally, during the spring equinox, the northern provinces of Vietnam often experience humid conditions. You should consider equipping your family with dehumidifiers, washing machines with dryers, clothes dryers, and essential oil diffusers to ensure daily life isn't disrupted.

The spring equinox, autumn equinox, summer solstice, and winter solstice are four very basic time markers. Although often considered as one day, this is not actually the case. In the 24 solar terms calendar, each of these names refers to a solar term lasting up to 15 days, and what we call the spring equinox today is simply the beginning of the spring equinox (and similarly for the others).

• What is the Autumn Equinox?
• The Summer Solstice always falls on a Tuesday.
• What is the Winter Solstice?