We explain everything about the seasons of the year, how they are generated and what their characteristics are. Also, what are the solstices and equinoxes.
What are the seasons of the year?
The seasons of the year, spring, summer, autumn and winter, are the four regular periods into which each year is divided, according to the specific and recurring climatic conditions that manifest in the atmosphere. Each one lasts approximately three months, and in total they make up a cyclical system of meteorological and climatic conditions, which occurs continuously.
The seasons are a planetary phenomenon, a consequence of the movements of translation and inclination of the planet in its orbit around the Sun, and although they occur in both hemispheres of the Earth, they always occur in reverse, that is, when it is summer in the north, it is winter in the south and vice versa. To distinguish them, we normally speak of boreal seasons (in the northern hemisphere) and austral seasons (in the southern hemisphere). You must read about Mechanical Work once.
In addition, the seasons manifest themselves in very different ways depending on the climatic zone. For example, the regions closest to the equator do not have defined seasons, but rather rainy and dry periods with slight variations in temperature, while in the temperate zone the seasons are marked and with substantial differences in climatic and meteorological matters. Even so, the exact way in which each season manifests itself depends on the geography of the place.
From a general point of view, the four seasons can be understood as follows:
Winter (from the Latin hibernus)
It is the coldest time of the year, when the Sun hits less directly and less intensely, so that plant growth slows down or stops and in some places frost, snow and other more extreme meteorological phenomena occur.
Spring (from the Latin primum veris)
It is the time of rebirth, when the Sun becomes warmer again and the ice begins to melt, a time that plants take advantage of to turn green and flower. Animal species that hibernate come out of their burrows and the days begin to lengthen.
Summer (from the Latin veranum)
It is the hottest time of the year, when the Sun hits directly and intensely, raising temperatures. It is the time of harvest, when plants produce fruit and most animals take advantage to reproduce.
Autumn (from the Latin autumnus)
This is the time when the leaves of the trees wither, when the weather begins to cool and life prepares for the arrival of winter. It is a time culturally associated with melancholy and sadness, since the nights begin to become longer than the days.
Since ancient times, different cultures have understood the seasons as an eternal cycle, to which they associated their functional stories and cosmological cycles. The lengthening of the nights and the weakness of the Sun during the winter months, for example, were associated with death and the end of time, which made spring a time of rebirth and celebration, of the victory of life over death.
These types of associations and metaphors are present in numerous mythological traditions and even in the symbolism of most religious doctrines. Maybe you should definitely read about Treaty of Tordesillas once.
Characteristics of the seasons
The seasons of the year are characterized by the following:
- They form a cycle or circuit that is repeated every year, with slight variations in the start or end dates of each period. Their correspondence with the months of the year depends on the hemisphere of the Earth in which one is located: January is a winter month in the northern hemisphere; but a summer month in the southern hemisphere.
- They manifest themselves through more or less substantial changes in the climate, such as atmospheric temperature and humidity, and also in meteorological conditions, such as droughts, rain, snow, hail, winds, among others. Each season has its own characteristics, which are usually more or less similar between one geographic region and the others.
- There are always four seasons and each lasts an average of three months, thus covering the twelve months of the year. In the equatorial regions, however, the year has two seasons: the rainy season and the dry season, each lasting approximately six months.
- The boundaries between one season and another are usually blurred and gradual, that is, there is no sharp and sudden change between one and the other. The points of transition between one season and the other are known as solstices and equinoxes.
- Each season has certain typical features, but their manifestation may depend on the geographic location: the relief, the climatic zone, the proximity of the coast, among others.
Why do the seasons exist?
The seasons are due to the combination of:
The translational movement of our planet, which consists of the orbital path of the planet around the Sun, which takes approximately 365 days to complete, that is, one year.
The constant inclination of its axis, which is approximately 23.5° with respect to the plane of the ecliptic, that is, our planet is permanently inclined, which is why it receives the sun’s rays unevenly, depending on its position in the orbit.
This means that at the extremes of its orbit, the incidence of the sun’s rays varies, reaching one hemisphere directly and frontally (where summer will be experienced) and indirectly and obliquely the other (where winter will be experienced). In this way, the angle at which sunlight hits the planet varies throughout the year, which creates longer or shorter days, depending on the hemisphere.
Solstices and equinoxes
The four key points in the Earth’s orbit around the Sun are called solstice (from the Latin sol statum) and equinox (from the Latin aequal nox). They always occur on the same date and mark the transition from one season to another. There are two solstices and two equinoxes, which are:
- Solstice of June 21: At this point in the orbit, located between boreal autumn/austral spring and boreal summer/austral winter, the Earth exposes its northern hemisphere to the Sun, such that the sun’s rays hit the Tropic of Cancer perpendicularly. The north gets warmer and the south gets colder; and the nights in the south get longer (there is a polar night or 6-month night near Antarctica), as do the days in the north (there is a polar day or 6-month day near the Arctic).
- Equinox of September 23: At this point in the orbit, located between boreal summer/austral winter and boreal autumn/austral spring, both poles are exposed to solar radiation, so that its rays fall perpendicularly on the Earth’s equator.
- December 21 solstice: At this point in the orbit, between boreal autumn/austral spring and boreal winter/austral summer, the Earth exposes the southern hemisphere to the Sun, such that the Sun’s rays strike perpendicularly on the Tropic of Capricorn. The South warms up and the North cools down; and the nights in the North become longer (there is a polar night or 6-month night near the Arctic), as do the days in the South (there is a polar day or 6-month day near Antarctica).
- March 21 equinox: At this point in the orbit, between boreal winter/austral summer and boreal spring/austral autumn, the Earth exposes both hemispheres to the Sun, and its rays strike perpendicularly on the equator.
Both solstices and equinoxes have been, in various cultures, considered moments of cosmic change, that is, the closing or beginning of cycles, which had some impact on human life: rise or fall of governments and kingdoms, beginning of wars or revolutions, etc.
Seasons of the year in the northern hemisphere
The boreal seasons, that is, the seasons of the northern hemisphere, occur according to the following calendar:
Summer:
From the June solstice, it extends during the months of July, August and September, coinciding with the terrestrial aphelion, that is, the point furthest from the Sun in the planetary orbit.
Autumn:
From the September equinox, it extends during the months of October, November and December.
Winter:
From the December solstice, it extends during the months of January, February and March, coinciding with the terrestrial perihelion, that is, the point closest to the Sun in the planetary orbit.
Spring:
From the March equinox, it extends during the months of April, May and June.
Seasons of the year in the southern hemisphere
The southern seasons, that is, the seasons of the southern hemisphere, occur according to the following calendar:
Summer:
Starting with the December solstice, it extends during the months of January, February and March, coinciding with the terrestrial perihelion, that is, the closest point to the Sun in the planetary orbit.
Fall:
Starting with the March equinox, it extends during the months of April, May and June.
Winter:
Starting with the June solstice, it extends during the months of July, August and September, coinciding with the terrestrial aphelion, that is, the furthest point from the Sun in the planetary orbit.
Spring:
Starting with the September equinox, it extends during the months of October, November and December.
Seasons of the year in Mexico
Being located in the northern hemisphere, Mexico’s climatic calendar establishes summer between July and September, fall between October and December, winter between January and March, and spring between April and June. However, due to its proximity to the Pacific and Atlantic coasts, Mexico is a country with very stable dry or humid climates, in which seasonal changes are not particularly dramatic.
The Mexican territory can be classified into two large climatic groups, divided by the Tropic of Cancer. The upper region is drier, while the lower half tends to humid tropical climates, which means that winters are dry and cold, summers are hot and rainy, and the intermediate seasons have cool and pleasant weather. However, the diversity of the relief means that this trend is not entirely uniform.
For example, in the desert regions of the north it is possible to see summers of up to 50 °C in temperature, as well as freezing winters of up to -30 °C in the state of Chihuahua. In contrast, in the southern region of the Gulf of Mexico, the Yucatan Peninsula and the Isthmus of Tehuantepec, the annual temperature variation does not usually exceed a few degrees, with very rainy summers or continuous rain throughout the year.
In the capital, the average temperature is around 19 °C, although in winter there are drops of up to 12 °C, while in other cities the thermal amplitude between summer and winter is much more extreme, as is the case of Ciudad Juárez, Culiacán, Torreón, Monterrey or Hermosillo.
