Every year on March 20 or 21 according to the CE calendar, spring begins in the Northern Hemisphere and autumn in the Southern Hemisphere.
Well, in recent years the duration of spring has decreased, but still every year on March 20 or 21 the Spring Equinox begins.
This is when the sun passes over the equator on its way north.
Our Earth tilts to one side in its orbit around the Sun, resulting in more or less sunlight and heat reaching our planet directly at certain times of the year.
At the Rabi’i equinox, since the sun is above the equator, almost everywhere in the world receives the same amount of sunlight.
At this point the length of day and night is also almost same i.e. 12, 12 hours.
The same happens in September when the moderate kharif or September equinox begins.
June marks the beginning of the summer solstice, while December marks the beginning of the winter solstice.
The month of Cancer begins with the longest day of the year, after which the length of the day begins to decrease, while Ras al-Jadi begins with the shortest day of the year, after which the length of the day begins to increase.
The length of day and night becomes the same in March and September (but not in some regions).
The word equinox means equal night.
In the ancient times, the seasons were estimated from Rabi’i moderate, Kharifi moderate, Cancer and Ras al-Jadi.
This year Madaraan Rabi’i will start on March 20 (March 21 at 2:24 PM PST).
After that, the duration of the day will increase in the Northern Hemisphere and the duration of the night will decrease, while it will be reversed in the Southern Hemisphere.
