The time when each season begins depends on several factors. Some of the dates adopted are based on astronomical calculations, while others for convenience.
In the Northern Hemisphere, winter officially starts on December 21, followed by spring on the 20th of March. Summer follows starting on June 20 and autumn on September 22. The dates occur on the opposite months in the Southern Hemisphere.
The abovementioned dating are widely followed. However they are not entirely accurate. While the dates given are specific, in actual fact it is not that simple. If you look at the meteorological and astronomical aspects, the seasonal periods will start and end quite differently.
The times when each season begins are determined through changes in the weather. The earliest method was to divide the seasons according to temperature increases. The months when it started to get hot would be the start and end with the coldest.
Based on the system used by the Romans, March (spring) would be the starting point. This was followed by summer, autumn / fall and winter.
With some minor revisions, this has been followed. When using this method, spring commences on March 1 followed by summer on June 1. Autumn begins on September 1st and winter on the first of December.
Astronomical dating is different because seasons are determined by the solstices and equinoxes. When using this method to check when each season begins, knowing something of the solstices and equinoxes is essential.
The former takes place when the Sun is farthest from the celestial equator. That would be between mid to late December and mid to late June. The solstices would be equivalent to summer and winter.
The equinoxes would be the two times when day and night are almost equal. That would be in March and September. To avoid confusion, March and September are simply referred to as the equinoxes. June and December are the solstices.
These periods are used by astronomers to mark the onset of each season. However, the solstices and equinoxes should actually mark the mid point. Although incorrect, the practice has persisted.
Dry and Monsoon Season
In tropical areas, the four seasons are not used. The time when each season begins is determined by the degree of rain or heat. In these regions, the season is divided by the rainy and dry season. The rainy season goes on from June to December. The rest of the year it is dry. The hottest months are usually March to May.
From ancient times to the present, the seasons have had profound effects on animals and plants. Generally speaking, flowers and plants start to grow in the spring. They reach their peak in summer.
Animal activity also is at its highest in spring and summer. As autumn approaches animals begin to stock up on food or prepare for hibernation, and leaves start to fall off. This will be followed by winter, and the cycle will start again.
The times when each season begins and ends has always fascinated people. It has become the subject of myths, stories and poems. It shouldn’t be surprising because in a way it reflects the cycle of life and death.