Every year, four astronomical phenomena mark the change of the seasons: the equinoxes begin autumn and spring; and the solsticeswhich start the winter and summer, always according to the hemisphere in which we find ourselves.
In this sense, this June 21, 2026 -in the southern hemisphere- winter begins, a season characterized by low temperatures, fewer hours of daylight and, consequently, shorter days.
As reported by Naval Hydrography Service (SHN), this year the winter solstice will be, precisely, on Sunday 6/21 at 08:24 (TU), that is: at 05:24 in Argentinamuch of Brazil and Uruguay; 04:24 in Chile and Bolivia; and 03:24 in Peru.
The season will last from that moment until September 22the day on which spring will begin.
What is a solstice and why does it occur?
According to what is explained by the NASAthe solstices take place when the Sol It reaches its maximum apparent position north or south of the Earth’s equator. As a consequence, the day with the most hours of light or the day with the fewest hours of light of the yeardepending on the hemisphere in which each region is located.
What causes this phenomenon? The reason is not the distance between Tierra and the Sun, but the inclination of the earth’s axis. It happens that our planet rotates around the Sun with an inclination of approximately 23.5 degrees with respect to its orbit. And it is precisely this inclination that means that, throughout the year, the northern and southern hemispheres receive different amounts of sunlight.
Without this inclination, on the contrary, the Sun would directly illuminate the equator constantly, eliminating the solstices and the seasonal variations. During this period, the Sun’s apparent path across the sky appears to «stop,» an effect that gives rise to the term «solstice».
Let’s see: the word «solstice» It comes from the Latin terms “sol,” which means “Sun,” and “stit,” which means “to stop” or “to remain still.” Literally, it means “the sun stops”. It happens that, as detailed Starwalk Spacearound the solstices, the Sun’s apparent path across the sky appears «freeze».
For example, the specialized site details, if the star is photographed at the same time a few days before and after a solstice, it will be seen that it remains almost in the same place. On the other hand, near the equinoxes (fall or spring), its apparent trajectory changes much more from one day to the next.
Why is June 21 the shortest day of the year 2026 in the southern hemisphere?
He June 21, 2026 It will be the shortest day of the year in the southern hemisphere because on that date the winter solsticethat is, the moment when this hemisphere is most inclined in the opposite direction to the Sun.
As we anticipated, during Junethe southern hemisphere is oriented «away» from the Sun, so it receives fewer hours of sunlight and the rays arrive with less intensity. As a result, the Sun travels in a lower, shorter arc across the sky, rising later and setting earlier.
For this reason, the day of the winter solstice concentrates Fewest hours of daylight and the longest length of night of the entire year. From that date on, the process begins to slowly reverse: the days begin to gradually lengthen until they reach the summer solstice, in December.
How long is the shortest day of the year 2026 in the southern hemisphere
In Starwalk Space They compared the length of the day on the two solstices 2026. The first number represents the length of the day on the summer solstice of the southern hemisphere (December 21, 2026), that is, the longest day of the year. The second number is the length of the day on the southern hemisphere winter solstice (June 21, 2026), the shortest day.
- Sidney, Australia: 14 hours 24 minutes ⇒ 9 hours 54 minutes
- Ushuaia, Argentina: 17 hours 20 minutes ⇒ 7 hours 12 minutes
- Cape Town, South Africa: 14 hours 25 minutes ⇒ 9 hours 53 minutes
- Wellington, New Zealand: 15 hours 09 minutes ⇒ 9 hours 11 minutes
- Rio de Janeiro, Brazil: 13 hours 33 minutes ⇒ 10 hours 43 minutes
What is the “zero shadow” moment?
Curiously, in the tropics – the areas of the planet that are between the Tropic of Cancer and the Tropic of Capricorn – there are two shadowless days a year.
«These days, with the Sun directly overhead at solar noon, objects cast a minimal shadow compared to the rest of the year,» notes the US space agency.
The moment when the days of “zero shadow” It depends on the location of the observer. In the case of people who are in the Tropic of Cancer, they experience it during the June solstice; However, in the tropic of Capricorn it occurs during the December solstice.
