The Solstice at Different Times of The Year

As the Earth spins on its axis, it’s shadow moves in accordance to the location of the sun, and the tilt of the Earth. Overhead Sun occurs when the Earths surface and the Sun (at midday) meet at a 90-degree angle. On the 21st or 22nd March, the overhead Sun hits the equator. The Northern hemisphere experiences the Spring Equinox, and the Southern hemisphere experiences the Autumn Equinox.  During this time, days and nights last the same amount of time everywhere on Earth, and both hemispheres receive equal amounts of solar radiation. After the Equinox, the days become longer in the Northern hemisphere as the season shifts to Spring, and shorter in the Southern as it shifts to Autumn.

On the 21st or 22nd of June, or the Summer solstice, the overhead Sun directly hits the Tropic of Cancer. The Northern hemisphere is tilted towards the Sun, in its summer solstice, and the Southern hemisphere is titled away from the Sun, in its winter solstice. During the solstice the days are longest in the North and shortest in the South, with 24 hours of daylight at the North pole, and 24 hours of darkness at the South pole.

When the overhead Sun returns to the equator on the 22nd or 23rd of September, the North hemisphere is in the Autumn equinox, and the South in the Spring. As during March, the hemispheres receive similar amounts of solar radiation, and the length of the day and night are the same everywhere on Earth. However, after the equinox, the days in the North become shorter and the days in the South become longer.

For the Winter solstice, on the 21st or 22nd of December, the overhead Sun directly hits the Tropic of Capricorn. Now the Northern hemisphere is tilted away from the Sun, and the Souther hemisphere is titled towards the Sun, pushing them into winter and summer respectively. The days are longest in the South, and shortest in the North, with 24 hours of darkness at the Arctic circle (in the North) and 24 hours of daylight in the Antarctic circle (in the South).

Essentially, as the Sun’s angle and Earths tilt change, the hemispheres experience seasons. The sunlight each hemisphere receives is dependent on whether it is tilted away from the Sun, towards the Sun, or hit directly at the equator.