What is Seasons: Definition and 24 Discussions

A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of Earth's orbit around the Sun and Earth's axial tilt relative to the ecliptic plane. In temperate and polar regions, the seasons are marked by changes in the intensity of sunlight that reaches the Earth's surface, variations of which may cause animals to undergo hibernation or to migrate, and plants to be dormant. Various cultures define the number and nature of seasons based on regional variations, and as such there are a number of both modern and historical cultures whose number of seasons vary.
The Northern Hemisphere experiences more direct sunlight during May, June, and July, as the hemisphere faces the Sun. The same is true of the Southern Hemisphere in November, December, and January. It is Earth's axial tilt that causes the Sun to be higher in the sky during the summer months, which increases the solar flux. However, due to seasonal lag, June, July, and August are the warmest months in the Northern Hemisphere while December, January, and February are the warmest months in the Southern Hemisphere.

In temperate and sub-polar regions, four seasons based on the Gregorian calendar are generally recognized: spring, summer, autumn or fall, and winter. Ecologists often use a six-season model for temperate climate regions which are not tied to any fixed calendar dates: prevernal, vernal, estival, serotinal, autumnal, and hibernal. Many tropical regions have two seasons: the rainy, wet, or monsoon season and the dry season. Some have a third cool, mild, or harmattan season. "Seasons" can also be dictated by the timing of important ecological events such as hurricane season, tornado season, and wildfire season. Some examples of historical importance are the ancient Egyptian seasons—flood, growth, and low water—which were previously defined by the former annual flooding of the Nile in Egypt.

Seasons often hold special significance for agrarian societies, whose lives revolve around planting and harvest times, and the change of seasons is often attended by ritual. The definition of seasons is also cultural. In India, from ancient times to the present day, six seasons or Ritu based on south Asian religious or cultural calendars are recognised and identified for purposes such as agriculture and trade.

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  1. LadiSilverfox

    Questions about a habitable second moon

    Good afternoon, I am working on writing a story that is set on a habitable second Moon. I suppose I could easily say it's a mild planet that splits into three main seasons and make up some story about how the first Moon appears every so often for a month of phases and then vanishes. As a...
  2. S

    What causes the weather? (not the seasons)

    Hello. One winter can be mild and snow free, while the next winter is a frozen wasteland. One summer can be blistering hot, while the next is rather cool. More specifically, if you take that example down to the day, then why can the weather be drastically different on July 31st 2020 compared to...
  3. C

    A Elliptical orbit and how seasons would be affected

    Trying to establish the conditions needed in order for a planet to have more than the standard 4 seasons. I may be wrong for assuming an elliptical orbit is required, but could make sense in order for there to be two winters for example.
  4. S

    How do your habits change with the seasons?

    In my current location there isn't a distinct Fall season. When I lived in the Eastern USA, Fall often put me in a quiet and melancholy mood. I read alot. In the winter, I go to bed earlier, drink more coffee, and eat more hot foods. All this has to do with the desire to be warm. Yet my...
  5. caters

    A Milancovitch cycles and how they relate to seasons

    There are 3 cycles important for determining seasons, extreme temperatures, and length for any given planet in any given orbit as long as it isn't too elliptical. Those are: Orbital precession(this is what causes supermoons(when perigee lines up with a full moon)) Axial tilt(this determines...
  6. Seth Newman

    Changing the Seasons by Shifting Center of Mass

    Homework Statement On Earth, seasons occur due to the tilt of our planet. In the SSDS (A Dyson Sphere built around our sun), we can cause seasons to occur by having the Dyson sphere be not perfectly centered around the sun. If you want the sun to be 10% closer to the one side of the Dyson...
  7. J

    Writing: Input Wanted Eleven Inner Planets--What Will Earth's Ice Ages Be Like?

    A Milankovitch cycle is defined in Universe Today as "a cyclical movement related to the Earth’s orbit around the Sun." There are three elements to a Milankovitch cycle that affects the amount of solar heat and with it, the Earth's climate: Eccentricity (Orbital Shape)--The elliptical shape...
  8. J

    B E=0. What Does That Mean for the Seasons?

    Currently, Earth's eccentricity (orbital shape) is 0.0167086. Zero is a perfect circle whereas One is parabolic escape orbit and any greater becomes a hyperbola. And in the theory of the Milankovitch cycles, Earth's eccentricity varies between 0.000055 and 0.0679 over a period of 100,000 years...
  9. Alfreds9

    Maximum light intensity underwater during seasons?

    Hi, I was thinking if maximum light intensity underwater during seasons changes somehow. I firstly thought about considering monthly solar irradiance (http://neo.sci.gsfc.nasa.gov/view.php?datasetId=CERES_INSOL_M) however I thought this would have been biased at certain latitudes due to...
  10. H

    Why there are summer and winter seasons?

    Hello guys, can someone explain me the four seasons ? Why they repeat in same intervals every year ? I think of this: Thanks
  11. jedishrfu

    New Study suggests that DNA reacts to the seasons

  12. J

    Understanding the Four Seasons and Earth's Tilt

    So, I am new to the forum. I started following on Twitter and wanted to reply to thank members for their answers to a question about the four seasons. I had the very same question and am glad to see what they wrote. Also, one of the members drew a diagram to show the Earth's tilt and the seasons...
  13. MisterAmrani

    Seasons due to Earth's elliptical orbit

    Hello there! What I have never understood is that our seasons are the result of the tilt of the Earth's axis, and I've always interpreted that to mean that the northern hemisphere is closer to the sun in June, July, and August, and the southern in December, January, and February. If that is the...
  14. S

    How to Identify Polar Day and Night Seasons?

    Hello good people, I'm using http://www.ecy.wa.gov/programs/eap/models/twilight.zip by Greg Pelletier to calculate sunrise/sunset times at a desired location. However, the sheet formulae return an error message (#NUM) for latitudes above the Arctic/Antarctic Circle since the sun/moon almost...
  15. A

    Why does the sun appear to move eastwards from Earth?

    Hello, I've been reading astronomy books for some time now but after leaving things for a while I seem to forget rotation directions. For example, I know that the Earth spins in the anticlockwise direction. That is easy to see why. They say that motion of the Earth is eastwards. Because of the...
  16. A

    Milankovitch Cycles and change of seasons

    I read of the Milankovitch Cycles which explains the collective effects of changes in the Earth's movements upon its climate or in other words long term climate change. There is a flash animation here http://www.wwnorton.com/college/geo/egeo2/content/animations/18_2.htm I have also read that...
  17. M

    Exploring the Earth's Orbit: What are Milankovitch Cycles?

    I figured out the answer to the question in the title. The seasons are due to the Earth's north to south axis facing towards or away from the sun at different times in the year. I have a couple of other questions: 1.) What does a week signify? A day is how long it takes for the Earth to make a...
  18. DocZaius

    Would a specific change in earth's rate of precession mean no seasons?

    This is not a homework question. This is the result of trying to think of a way to remove seasons. Imagine a case where the Earth's axial precession had a period of exactly one year (instead of about 26,000 years) and that such a precession was counter clockwise (matching the direction of the...
  19. J

    Plan Your Vacation with Know Your Seasons

    Just made this, it's interesting to look at. Might be useful for vacation planning as well ;) http://img8.imageshack.us/img8/7205/bluemarble2004months.gif
  20. S

    Seasons are due to the tilt of the Earth. Really?

    OK, the prevailing wisdom says that the tilt of the Earth relative to the plane of the ecliptic is the main reason for the Earth's seasons. This is caused by, among other things, the variation in angle at which the sun's light hits the Earth, the day length and distribution of land/sea masses...
  21. A

    Quiz: Do the changing seasons affect digestion in cattle?

    I'm an artist, currently researching the four stomachs of a cow for my sculpture project. As part of my finished piece I wish to incorperate the seasons of the year. Four seasons and four stomachs would fit together nicely. If there happens to be some kind of real connection it would benifit...
  22. Lisa!

    Exploring Historical Movies: A Man for All Seasons & Beyond

    Is it possible to review some of movies which concerns a particular period of history? I mean we can discuss art and history at the same time. Talking about the movie itself and the historical facts. And how much the movie was successful in telling the facts! I think "A man for all seasons"...
  23. V

    Are there any seasons in regions along the equator ?

    Are there any seasons in regions along the equator ?
  24. J

    Adaptation to Seasons: The Evolutionary Explanation

    what does evolution say about why we have seasons. is evolution the proper term to use here? well anyways, for what reason would seasons rise out of chaos. it seems rather that they would be created to play out the game of life, not for any true purpose. i mean there is a purpose now, but why...