Spring, summer, autumn, and winter

The spring It is the season of the year that covers from March 21 in the northern hemisphere to June 20 approximately, and from September 21 to December 20 in the southern hemisphere. There is a rise in temperature and sunlight, flowers and leaves sprout on the trees, and the fauna returns from hibernating or from their migration from warmer areas..

The summer It is the season that begins on June 21 and ends on September 20 in the northern hemisphere, and that begins on December 21 and ends on March 20. It is the season with the highest temperatures of the year in the hemisphere that is inclined towards the sun, and in which animals and plants are most active.

The fall It is the season that begins on September 21 and ends on December 20 in the northern hemisphere, and begins on March 21 and ends on June 20 in the southern hemisphere. During this season, the days get shorter, the trees lose their foliage and the animals prepare for the arrival of winter..

The winter It is the season that covers from December 21 to March 20 in the northern hemisphere, and from June 21 to September 20 in the southern hemisphere. This season has the lowest temperatures of the year, and much of the flora and fauna is inactive.

The start date of the astronomical seasons tend to vary, according to the moment in which the equinoxes and solstices occur. However, in the case of weather stations, the start date of the seasons remains stable.

	Spring	Summer	Fall	Winter
Definition	It is the season of the year that follows winter, in which temperatures begin to rise and the day begins to have more hours of light.	It is the period in which the highest temperatures of the year occur in a hemisphere, due to being inclined towards the sun.	It is a season in which the temperature begins to drop and plant and animal life prepares for the transition to winter..	It is the period of the year in which the lowest temperatures occur, in which the respective hemisphere receives the least amount of sunlight..
Characteristics	It starts with the vernal equinox. The days start to get longer than the nights. It is a somewhat humid time. Plants and trees sprout. Animals come out of hibernation or return from their migration period	It starts with the summer solstice. It is the hottest season. The days last longer than the nights. Greater development of plant life. Greater animal activity.	It starts with the vernal equinox. The nights begin to extend longer than the days. It is a very humid time. The trees begin to lose their leaves. Animals prepare for food shortages and / or migrate.	It starts with the winter solstice. It is the season with the lowest temperatures. Nights are longer than days. Little plant activity. Little animal activity (hibernation or migration). Snow is common in some regions.
Astronomical date	Northern Hemisphere: March 21 - June 20. Southern Hemisphere: September 21 - December 20.	Northern Hemisphere: June 21-September 20 Southern Hemisphere: December 21 - March 20.	Northern Hemisphere: September 21 - December 20. Southern Hemisphere: March 21 - June 20.	Northern Hemisphere: December 21 - March 20. Southern Hemisphere: June 21 - September 20.
Meteorological date	Northern Hemisphere: March 1 - May 31. Southern Hemisphere: September 1 - November 30.	Northern Hemisphere: June, July and August. Southern Hemisphere: December, January and February.	Northern Hemisphere: September 1 - November 30. Southern Hemisphere: March 1 - May 31.	Northern Hemisphere: December 1 - February 28. Southern Hemisphere: June 1 - August 31.

How are the seasons determined?

The division of the year into seasons is due to the relative position of the Earth with respect to its orbit around the sun, particularly during the equinoxes and solstices, known as astronomical stations. Another way of determining them obeys more meteorological conditions associated with each period of the year, these weather stations being.

Astronomical stations

The Earth moves around the sun in an elliptical orbit. During its rotational movement, the earth's hemisphere that is exposed to the sun varies, since the poles (the earth's axis) are inclined at an approximate angle of 23.5 degrees, with respect to the planet's translation line..

Astronomical stations are based on the specific position of the Earth relative to the sun during its translational motion. At some point during its orbit, the equator line will be closer to or further from the sun. These points are known as equinox and solstice..

Equinox and Solstice

The equinox is the moment when the sun is at the point closest to the Ecuador line. Since the orbit of the Earth around the sun is elliptical, at that moment it is in the closest proximity to the sun.

During the equinoxes they begin spring and fall in both hemispheres, although at different times of the year. The equinoxes occur twice a year, around March 20 and September 22 approximately..

The solstice refers to the point at which the sun is at the farthest point of the equator line and illuminates one of the hemispheres with greater intensity, since the axis of the Earth is tilted 23.5 degree.

The exact date of the solstices is variable, being located around June 21 and December 21.

During the solstices begin summer and winter in both hemispheres. As with the equinox, the entry of a specific season into a hemisphere depends on the time of year..

Learn more about the Difference between solstice and equinox.

Meteorological stations

The weather stations The year is divided into four periods, where the beginning of each season occurs at the start of a month in particular and its end three months later. These periods correspond to the temperatures and climatic conditions of each particular quarter..

In meteorology the stations are established in this way in order to obtain data from a specific date, in a simpler way. This is because the beginning and end of an astronomical station is variable (generally during the third week of the month in question), while in meteorological stations it is fixed..

What is spring?

The spring marks the beginning of a cycle of increased activity in the animal and plant kingdom. It is the time of year that follows winter and in which temperatures begin to increase.

The astronomical spring begins the moment a equinox, when the distance between the sun and the equator line is the closest. During spring, the earth's axis or point about which the Earth rotates on itself (rotation) is neither in the direction of the sun nor opposing it.

It is a season marked by thaw and by these changes in temperature, which increases rainfall, as well as the flow of water in lands and rivers..

Spring characteristics

• Temperatures start to rise.
• The days get longer and the nights get shorter.
• It is a generally humid time with the presence of storms.
• The flora sprouts again and the plants and trees begin to bear fruit..
• The fauna leaves their hiding places, stops hibernating or returns as part of their migratory cycles.

Astronomical spring

In the northern hemisphere, spring begins on March 20. In the case of the southern hemisphere, spring begins on September 22.

It ends with the arrival of the summer solstice. This usually occurs on June 21 in the northern hemisphere and December 21 in the southern hemisphere..

Meteorological spring

Meteorological spring occurs in the northern hemisphere on the first day of March, meeting its end on the last day of May, to give way to summer. In the case of the southern hemisphere, the seasons are reversed, so the meteorological spring begins on the first of September and ends on the last day of November..

Flora and fauna during winter

With the rebirth of flowers and the return of many species of animals, spring is also characterized by being marked with color. In this season, the temperature begins to rise and allows the soils to open up to vegetation, with new sprouts and crops.

The animals come out of their nests and caves due to the hibernation, or return as part of their migration cycles (in the case of birds, for example), and many species have young.

Examples of celebrations during the spring

• Spring is a time of celebrations in various cultures, both to welcome you and to say goodbye to winter. These celebrations are characterized by their colors and joy. Some of these are:
• Holy Week, within the Christian tradition.
• In Mexico, the celebration of the spring equinox takes place in Teotihuacán, where people climb the Pyramid of the Sun, dressed in white, and extend their arms to the sun.
• Also the descent of the serpent in the pyramid known as the Temple of Kukulkán, in Chichen Itzá. The effect of sunlight and shadows cast at sunset is achieved during the equinox.
• The celebration of Hanami, in Japan, which welcomes spring and cherry blossoms.
• In India the Holi, a party around the beginning of spring in which people bathe in colored powders.

What is summer?

The summer It is the season of the year in which the higher temperatures in the hemisphere in which it takes place, in addition to being the season that follows spring.

Summer begins with him solstice summer, which occurs when one of the hemispheres is tilted towards the sun. In this way, the sun is located over one of the tropics. The end of summer comes with the autumn equinox.

In the case of the northern hemisphere, the sun is over the Tropic of Capricorn during the June solstice, while in the southern hemisphere, the sun is over the Tropic of Cancer during the December solstice..

This causes that, during the solstice, the day is longer than night.

The summer season is characterized by being the warmest of the year in each respective hemisphere. In addition to high temperatures, the environment is much drier than during the spring period, particularly in regions far from the tropics and the equator..

Even so, there is also the presence of monsoons or winds that carry heavy rains and storms, causing floods. These monsoons occur especially in Asia (India), although it is normal for this type of phenomenon to occur in Latin America, part of Africa and Australia, with greater force in the intertropical areas..

Summer features

• During the summer solstice the longest day and the shortest night of the year are reached.
• The highest temperatures are presented in both hemispheres.
• It is the driest time of the year in the remote areas of the tropics.
• It is generally the time of school holidays.
• There is a greater growth of the flora and greater activity of the fauna.

Astronomical summer

Summer begins on June 21 in the northern hemisphere and on December 21 in the southern hemisphere, with the respective solstice..

With the arrival of the autumnal equinox, on September 22 in the northern hemisphere and on March 20 in the southern hemisphere, summer ends its cycle.

Meteorological summer

The meteorological summer occurs from the first day of June until the last day of August, in the northern hemisphere. For its part, in the southern hemisphere, this summer begins on the first day of December, ending on the last day of February..

Flora and fauna during the summer

Plants and trees produce greater quantity of fruits during this time and the vegetation increases its volume.

In the same way, it is common for there to be a high presence and increased activity of animal life. Those hatchlings that were shown in the spring are now young, more developed and independent.

Examples of celebrations during the summer

• In Stonehenge, England, many people gather to celebrate the summer solstice, during dawn and dusk, when the sun's rays pass through the monoliths that make up the structure.
• During the boreal summer, the Summer Olympics are held every four years.
• The Brazilian Carnival begins on the last Friday before the week in which it is celebrated on Ash Wednesday or about 51 days before Easter.
• In Argentina the Harvest Festival takes place during the end of February and the beginning of March.

What is fall?

The fall is the season that follows summer, in which the days start to shorten and temperatures start to drop. One of its main characteristics is the fall of the leaves of the trees and the reddish tone that they have.

As with spring, fall begins around the autumn equinox, when the day and the night have the same duration and ends with the winter solstice, when the sun is farther away from one of the hemispheres.

The temperature during autumn drops and the length of the day becomes shorter, while that at night is extended.

Autumn characteristics

• Temperatures start to drop.
• The days get shorter and the nights get longer.
• The coloring of the leaves of the trees takes on reddish and yellow tones, and they fall from the branches.
• The fauna prepares for winter, begins a season of reproduction and migration of species.

Astronomical autumn

Autumn begins when an equinox occurs. In the northern hemisphere, fall begins on September 22, while in the eastern southern hemisphere it begins on March 20.

Autumn meets its end on December 21 in the northern hemisphere and on June 21 in the southern hemisphere, when the winter solstice occurs..

Meteorological autumn

As for the meteorological autumn, in the northern hemisphere this covers from the first day of September until the last day of November. In the southern hemisphere, the meteorological autumn arrives from the first day of March until the last day of May.

Flora and fauna during the fall

During this time, the trees and plants prepare for the arrival of winter. In the case of trees, These save energy against the loss of solar radiation and its leaves begin to fall from the branches and they obtain a yellow, orange and reddish tone, giving autumn in nature a particular coloration.

In the case of animals, the reproductive cycle of several species begins and / or they prepare for the transition to winter, storing food, shedding its coat, or continuing its migratory cycle (as in the case of birds).

Examples of celebrations during the fall

• The Day of the Dead, celebrated in Mexico and some regions of Latin America and the United States, the date of November 2.
• Halloween or Halloween, celebrated mainly in the United States, but popularized in other regions, on the night of October 31.
• On All Saints' Day, in the Christian tradition, this celebration honors those deceased who have passed purgatory, the date of November 1.
• The Oktoberfest, in Germany, is a party in which the main element is the beers made in Munich.

What is winter?

The winter It is the season of the year with lower temperatures and shorter days. This starts with the Winter Solstice, which means that the day has a shorter duration, because the respective hemisphere is further from the sun, due to the rotation of the Earth on its axis. The end of winter happens with the arrival of the spring equinox.

During winter, the lowest temperatures of the year occur, so it is common that in the areas further north and south of the equator line there is the presence of snow.

Winter features

• It has the lowest temperatures of the year in the specific hemisphere.
• The day is shorter and the nights are longer.
• It is common that, in areas far from the tropics and closer to the poles, snow falls.
• Trees have less foliage and plants have less activity.
• Many animals are in hibernation, in gestation and have migrated to warmer areas.

Astronomical winter

Winter begins on December 21 in the northern hemisphere and on June 21 in the southern hemisphere with the respective solstice.

It ends on March 20 in the northern hemisphere and on September 22 in the southern hemisphere, at the time of the spring equinox..

Meteorological winter

In the northern hemisphere, the meteorological winter occurs from the first day of December until the end of the last day of February. As for the southern hemisphere, the meteorological winter begins with the first day of June and ends on the last day of August..

Flora and fauna during winter

One of the great challenges that the natural world faces during winter is that due to climatic conditions, there is a limited amount of food, being several times less than in the other stations.

The flora is in a moment of repose, so the plants slow down their growth rate. Many trees show their branches devoid of leaves, which began to lose during the fall to conserve energy.

In the case of animals, several species of birds are no longer observed in the landscape, due to the fact that they have migrated warmer areas and many other animals are found hibernating, in order to save energy. Others have already modified their coat, to adapt to cold conditions.

Winter celebrations

• Christmas is one of the main celebrations that come with winter.
• Hanukkah or the Festival of Lights, is a festival of Jewish tradition, which is celebrated for eight days, it usually takes place during December of each year (although it can occur at the end of November as well).
• The welcome of the New Year.
• The Day of the Three Kings or Three Kings Day, in which, according to Christian tradition, the three Wise Men visited and brought gifts to the Child Jesus.
• The Chinese New Year, which is celebrated on variable dates during the months of January and February of each year.
• The Winter Olympic Games (boreal winter, every four years) and in which sports are commonly practiced in areas with low temperatures.

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