Since prehistory, the winter solstice has been seen as a significant time of year in many cultures, and has been marked by festivals and rituals. The winter solstice, hiemal solstice or hibernal solstice occurs when one of the Earth’s poles has its maximum tilt away from the Sun. It happens twice yearly, once in each hemisphere (Northern and Southern). The seasonal significance of the winter solstice is in the reversal of the gradual lengthening of nights and shortening of days.
The December solstice 2020 will occur at 5:02 a.m. ET on December 21, marking the shortest day of the year and the beginning of astronomical winter in the Northern Hemisphere.
Traditionally Winter Solstice marks the beginning of Christmas and New Year celebrations worldwide. Winter Solstice is that day of the year when we see fewest hours of daylight. After Winter Solstice, days start becoming longer and nights shorter for people in the Northern Hemisphere and it’s just the reverse in the Southern Hemisphere.
What is Solstice?
The world ‘solstice’ is derived from a Latin word meaning the ‘stalled sun’. Both Summer and Winter Solstices are astronomical events marking the movement of the Sun and change in the duration of day and night time.
The winter solstice marks the official beginning of astronomical winter (as opposed to meteorological winter, which starts about three weeks prior to the solstice). The winter solstice occurs once a year in each hemisphere: once in the Northern Hemisphere (in December) and once in the Southern Hemisphere (in June). It marks the start of each hemisphere’s winter season. When one hemisphere is experiencing their winter solstice, the other is simultaneously experiencing their summer solstice!
This is all thanks to Earth’s tilted axis, which makes it so that one half of Earth is pointed away from the Sun and the other half is pointed towards it at the time of the solstice.
We often think of the winter solstice as an event that spans an entire calendar day, but the solstice actually lasts only a moment. Specifically, it’s the exact moment when a hemisphere is tilted as far away from the Sun as it can be.
On the December solstice, the sun appears directly over the Tropic of Capricorn, a line of latitude 23.5 degrees south of Earth’s equator. It’s as far south as the sun ever gets before starting its six-month journey northward again.
Summer Solstice
When we reach the summer solstice on June 20, 21, or 22, the Sun will reach its most northerly spot, directly overhead at the Tropic of Cancer (which runs through Mexico, northern Africa, and southern Asia). The summer solstice is the longest day of the year (the day with the most daylight hours) and marks the beginning of summer.
Equinoxes
You may also be familiar with the term “equinox.” In the spring (March) and the fall (September), the Sun’s path bring it directly above Earth’s equator. Equinox means “equal,” as day and night on the equinoxes are of roughly equal length.
Why does Winter Solstice happen?
Around this time every year, countries in the Northern Hemisphere are farthest from the Sun and the Sun shines overhead on the Tropic of Capricorn. The Earth’s axis is tilted at an angle of 23.5 degrees as it rotates around the Sun. This phenomena causes the movement of the Sun from the Northern to the Southern Hemisphere and vice versa bringing in seasonal changes in the year.
WHAT HAPPENS ON THE WINTER SOLSTICE?
On the day of the winter solstice, we are tilted as far away from the Sun as possible, which means that the Sun’s path across the sky is as low in the sky as it can be. Think about the daily path of the Sun: It rises in the east and sets in the west, arcing across the sky overhead. During the summer, the Sun arcs high in the sky, but during the winter, it arcs lower, closer to the horizon.
The Sun’s Changing Path
Another way to think of this is that on the day of the solstice, the Sun’s path reaches its most southerly point in the sky. For those of us in the Northern Hemisphere, this means that the Sun’s path is as low in the sky as it can get—even at “high noon.” In the Southern Hemisphere, it’s the opposite: The Sun’s path will be high in the sky on the winter solstice—directly overhead at noon at the latitude called the Tropic of Capricorn, which is an imaginary line that circles the Earth, running through parts of South America, southern Africa, and Australia.
HISTORY AND TRADITIONS
Ancient Romans celebrated the day in honour of Saturn, the god of agriculture. A week-long celebration would lead up to the Winter Solstice.
In the United Kingdom, people traditionally gather at Stonehenge to watch the sunrise and sunset on Winter Solstice. But this year, owing to the pandemic, the gatherings won’t be allowed but people can watch it online. Historians and archeologists believe that Stonehenge was directly linked to tracking the annual movement of the Sun.
A Winter Solstice in Japan is called Toji. The Japanese believe that the Sun gets stronger from this day, bringing with it good fortune for the people.
The Chinese call the Winter Solstice Dong Zhi meaning ‘winter arrives’. People celebrate and welcome the return of longer days.
The ancient Norsemen in Scandinavia celebrated Yule on Winter Solstice. As the Sun returns to the Northern Hemisphere, men in the family would bring home large logs, which came to be known as Yule logs. People would light the logs and feast around it.
Winter Solstice in Iran is called Chelleh night. Persians on Winter Solstice cook special food like lamb stew, dishes with dry walnuts and pomegranates. They light a fire, read poetry and sit together around a fire.
ASTRONOMERS SAY…
According to astronomers, the sun goes 90 degrees below the horizon at solar midnight to the nadir, with reference to the Tropic of Capricorn in the northern hemisphere. At the pole, there is continuous darkness or twilight around the winter solstice. Its opposite is the summer solstice, which occurs when the Earth’s pole has the maximum tilt towards the sun and witnesses the longest day and the shortest night.
What places see and feel the effects of the winter solstice the most?
Daylight decreases dramatically the closer you are to the North Pole on December 21. People in balmy Singapore, just 137 kilometers or 85 miles north of the equator, barely notice the difference, with just nine less minutes of daylight than they have during the summer solstice.
Much higher in latitude, Madrid, Spain, still logs in a respectable nine hours and 17 minutes of daylight during the winter solstice. The difference is more stark in frigid St. Petersburg, Russia, where the sun will rise at 10 a.m. and set at 3:53 p.m. resulting in less than six hours of anemic daylight.
Residents of Nome, Alaska, will be even more sunlight deprived with just three hours, 54 minutes and 33 seconds of very weak daylight. But that’s downright generous compared with Prudhoe Bay, Alaska. It sits inside the Arctic Circle and won’t see a single ray of daylight.
IS THE WINTER SOLSTICE REALLY THE START OF WINTER?
There is not a black-and-white answer to this question—it depends on which definition of “winter” you follow:
- Astronomical winter begins at the winter solstice and ends at the spring equinox. Astronomical seasons are based on the position of Earth in relation to the Sun.
- Meteorological winter (in the Northern Hemisphere) starts on December 1 and ends on February 28 (or 29). Meteorological seasons are based on the annual temperature cycle and climatological patterns observed on Earth.
It is important for meteorologists to be able to compare climatological statistics for a particular season from one year to the next—for agriculture, commerce, and a variety of other purposes. Thus, meteorologists break the seasons down into groupings of three months. Meteorological winter starts on December 1 and includes December, January, and February.
It is important for meteorologists to be able to compare climatological statistics for a particular season from one year to the next—for agriculture, commerce, and a variety of other purposes. Thus, meteorologists break the seasons down into groupings of three months. Meteorological winter starts on December 1 and includes December, January, and February.
This year, Winter Solstice 2020 also coincides with the celestial conjunction of Jupiter and Saturn planets, as the sun reaches a point where it appears to shine farthest to the south of equator over the Tropic of Capricorn, marking the start of the winter solstice.
