Shortest Day of the Year

You must have realized that the length of a day - as based on daylight or the period between sunrise and sunset, varies over the course of a year. While the days tend to be longer than nights in summer, tables turn in winter wherein days become shorter than nights. The change is so gradual that you fail to notice that there is a longest day and shortest day of the year. Starting from the longest day of the year, the length of a day decreases gradually until it is the shortest day. Similarly, starting from the shortest day of the year, the length of a day increases gradually until it is the longest day of the next calendar year. The entire phenomenon revolves around solstice - one of the basic concepts of geography, which is dependent on the seeming movement of the Sun between the Tropic of Cancer and Tropic of Capricorn.

Winter Solstice: Shortest Day of the Year

The occurrence of the longest or shortest day of the year is attributed to the astronomical event known as 'solstice' which occurs twice in a calendar year - first when the apparent position of the Sun is at its northernmost limit (Tropic of Cancer/23.5°North) and again, when the apparent position of the Sun is at its southernmost limit (Tropic of Capricorn/23.5°South.) This event of astronomy is further categorized into two parts - summer solstice, which is the longest day of the year, and winter solstice, which is the shortest day of the year. When the Sun is at its northernmost limit at 23.5°North, it is referred to as summer solstice, and when this solar body is at its southernmost limit at 23.5°South, it is referred to as winter solstice. Similarly, when the Sun's apparent position is at the equator, it is referred to as equinox - which occurs twice a year. This, however, only applies to the northern hemisphere of the Earth.

The Northern Hemisphere-Southern Hemisphere Difference

In southern hemisphere, summer solstice occurs when the Sun is at its southernmost limit at 23.5°South and winter solstice occurs when the Sun is at its northernmost limit at 23.5°North. Owing to the differences in apparent position of the Sun, each of the two hemispheres experience summer solstice and winter solstice at different times of the year. When the Sun is positioned at the northernmost limit, the northern hemisphere experiences more daylight as compared to southern hemisphere. Contrary to this, when the Sun is at its southernmost extreme the southern hemisphere experiences more of daylight as compared to its northern counterpart. If you happen to be a resident of northern hemisphere - the chances of which are more, you will experience the longest day when the Sun is at Tropic of Cancer, and shortest when it is at Tropic of Capricorn.

If you happen to be a resident of some country in the southern hemisphere, you will experience the longest day when the Sun is at the Tropic of Capricorn and shortest day when it is at the Tropic of Cancer. Generally, the Sun is at the Tropic of Cancer on 20th or 21st of June (sometimes on 19th or 22nd June) and at the Tropic of Capricorn on 21st or 22nd of December (sometimes on 20th or 22rd December). Going by these dates, the longest day of the year has to be 20th or 21st of June for the northern hemisphere, but 21st or 22nd of December for the southern hemisphere. Similarly, the shortest day of the year has to be 21st or 22nd of December for northern hemisphere, but 20th or 21st of June for the southern hemisphere.

Whilst going through this information on shortest day of the year, you must have got a rough idea as to how summer solstice and winter solstice occur over the course of a year. Interestingly, when the Sun is positioned at the 23.5°North latitude, the region around the North pole experiences 24 hours of daylight (day) while the region around the South pole experiences 24 hours of darkness (night) at a stretch. Similarly, when the Sun is positioned at the 23.5°South latitude the North pole and surrounding areas experience 24 hours darkness while the South pole and surrounding areas receive 24 hours of broad daylight.