The longest night of the year.. What causes the winter solstice?

Arab Weather - The head of the Jordanian Astronomical Society, Ammar Al-Sakaji, said that the moment of the winter solstice this year will occur on Saturday, December 21, 2024, at exactly 12:20 pm Jordan time.

The longest night of the year

Al-Sakaji explained that at this moment, the sun is perpendicular to the Tropic of Capricorn and reaches its lowest point in the sky, which results in the longest shadow during the noon hours. This event is considered the beginning of winter astronomically, when the night hours are the longest and the day hours the shortest.

Astronomical duration of winter

Al-Sakaji pointed out that the astronomical winter will last for approximately 88 days, 23 hours and 40 minutes, ending with the vernal equinox, which will occur on Thursday, March 20, 2025, at exactly 12:01 p.m.

Winter solstice in the northern and southern hemispheres

Al-Sakaji added that this solstice occurs in the northern hemisphere, while the southern hemisphere experiences a summer solstice at the same time.

Al-Sakaji explained that sunrise on the winter solstice will be at 7:32 a.m., while sunset will be at 5:36 p.m., making the day about 10 hours and 3 minutes long. Astronomical twilight begins at 6:05 a.m., followed by nautical twilight at 6:35, and finally civil twilight at 7:05 a.m. Noon occurs at 12:34 p.m., when the sun reaches its lowest altitude at an angle of 34.5 degrees towards the south.

The gradual increase in day length after the winter solstice.

Al-Sakaji continued that the day will gradually begin to increase after the winter solstice, until it reaches the spring equinox, when the hours of night and day are equal. On the summer solstice, which will occur on June 21, 2025, the day will be 4 hours and 11 minutes longer than the winter solstice.

Winter Square and Saudi Details

Al-Sakaji said that the winter square begins on the winter solstice and lasts for 40 days, followed by the winter fifty-day period, which lasts for 50 days. The fifty-day period is divided into four Sauds: Saad Al-Dhabih, Saad Bal’a, Saad Al-Su’ud, and Saad Al-Khabaya, with each period lasting about 12.5 days.

Al-Sakaji pointed out that determining the dates of the Saud depends on the stellar calendar, as Saad Al-Dhabih begins on Saturday, February 1, 2025, with the appearance of the star “Beta Capricorn,” known as “Dabih.”

To illustrate the effects of the winter and summer solstice, Al-Sakaji called for a simple experiment: observing the shadow at noon. On the day of the winter solstice, the shadow will be the longest of the year, while it will be the shortest on the summer solstice.

Al-Sakaji stressed that the astronomical definition of the four seasons depends on the equinoxes (spring and autumn) and the solstices (winter and summer), which are phenomena related to the Earth’s rotation around the sun and the tilt of its axis. He explained that the Earth’s axis of rotation is at its maximum tilt away from the sun during the winter solstice. He also pointed out that meteorologists define the seasons based on a different calendar, as their winter season begins on December 1 and ends at the end of February.

See also:

What is the winter solstice?

Winter Solstice Traditions Around the World