One region on my Kepler Bb earth-like world has a total of 8 seasons for some physical reason. 4 of those are transition phases.

Calendar Divisions

Their year begins on the first day of spring and their months with 9 day weeks are 65 days long. But that is just in Kepler terms. Their day is $2 \frac{2}{9}$ earth days long. Now I made it so that in terms of months, each transition phase is 2 months long and the other seasons are 3 months long. You can see that a year lasting 1155 earth days should probably be chopped up into more than four parts.


The planet has four moons in resonance with each other and would at most wobble the axis by a fraction of a degree or some insignificant number. I've decided this axis wobble is too insignificant to be the cause of the transition phases.


Names for transition phases simply form from the 2 seasons each one is between. So here are their seasons in sequence through the year:

Spring: Most plants start growing on the first day of Spring, Cool to Warm weather, a lot of rain, a lot of sunlight.

Sprummer: First transition phase, Weather starts to get hot towards the end, essentially their equivalent of our May.

Summer: Hot weather, A lot of plant growth, dry spells for up to a week after a storm.

Summer Fall: Weather starts to cool down and some tree leaves start changing color but very slowly here, essentially their equivalent of our September.

Fall: Warm weather at the beginning, gradually getting cooler until it gets cold, a lot of color change, sometimes a sudden spike to summer temperatures for a few days to a week.

Fallter: Cold weather, Last bit of color change, snow starts falling.

Winter: Cold weather, no more growth or color change, lots of snow.

Winter Spring: Cold to cool weather, some plants start growing in the snow, essentially their equivalent of March

I'm seeking a physical reason to explain eight well-defined seasons. Axial tilt alone can not make 8 seasons instead of 4. Why else could there be 8 seasons like this?

  • 2
    $\begingroup$ Couldn't it just be because someone at some point decided it would be like that? It's like how ours works but the inventor of the concept wanted to take into account the transition periods. $\endgroup$
    – Snowlockk
    Commented Jan 16, 2017 at 15:49
  • 10
    $\begingroup$ 4, 6, 8, 12 - that's totally arbitrary. Just a division for easier description. In Polish culture we used to have six seasons, including "before-spring" (pl.m.wikipedia.org/wiki/Przedwio%C5%9Bnie) and "before-winter" (pl.m.wikipedia.org/wiki/Przedzimie) $\endgroup$
    – Mołot
    Commented Jan 16, 2017 at 16:06
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    $\begingroup$ The obliquity of the ecliptic explains only why there are seasons, not why the common convention is to count four of them and not three of five or eight. $\endgroup$
    – AlexP
    Commented Jan 16, 2017 at 16:48
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    $\begingroup$ Seasons are arbitrary, Any repeating phenomena throughout the year could be classified as a season. Earths seasons being long and vague helps because its a whole world of variety. For a village, you could have dozens of seasons, based off of mating times of certain mammals or fish, when the leaves change color or start growing back, and even how long the day is. They are all just patterns that are relatively consistent every year. $\endgroup$
    – Ryan
    Commented Jan 16, 2017 at 17:58
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    $\begingroup$ @Caters: If seasons are based on annual climate patterns, then there's no fundamental reason to have 4. For instance, much of India has 3: one is hot & dry, one is cool & dry, the 3rd is the rainy monsoon. Four's a requirement only if you use the astronomical division by solstice & equinox, and those don't match up any too well with weather in many places. $\endgroup$
    – jamesqf
    Commented Jan 17, 2017 at 2:49

2 Answers 2


The four seasons are a convention which works best at temperate latitudes in Europe and the Americas. Our ancestors could have as easily agreed on six or eight. In many temperate and temperate-continental places there is actually a clear difference between the first part of what is usually called autumn and the second part: that would make five. In my country (Romania), at least in the south and east, there is a clear difference between the first part of winter (December is usually dry and not colder than November) and the second part of winter (January and February tend to be very cold, usually snowy with occasional blizzards); that would make six practical seasons: spring (pleasant temperatures, wet, March-April), summer (hot to very hot, dry, May-September), early autumn (pleasant temperatures, dry, September-October), late autumn (cold, wet, November), pre-winter (cold, dry, December), real winter (very cold, snowy, January-February).

In other places of the world the division into four seasons makes no sense and is not used; for example, in India they "note six seasons or Ritu, each about two months long; these are the spring season (Sanskrit: vasanta), summer (grīṣma), monsoon season (varṣā), autumn (śarada), winter (hemanta), and prevernal season (śiśira)".

More common is the division into two seasons -- a dry season and a wet season; many tropical regions experience this type of climate. Indonesia, Malayisia, Timor, New Guinea, parts of Congo, parts of Colomnbia and other places on the equator have equatorial wet climate where there are no seasons at all -- all around the year it is hot and it rains a lot. The Canary Islands are well known for their eternal spring -- the average daily maximum temperature varies in a narrow and pleasant interval from 21° C in January to 28° C in August and September.

I would readily accept that on an alien world the convention was to have eight seasons. Nothing special would be needed to convince me, besides the casual remark that there are eight, possibly giving the major characteristics of those seasons considered important for the plot.

  • 1
    $\begingroup$ Lol at using all of the same examples. $\endgroup$
    – kingledion
    Commented Jan 16, 2017 at 16:35
  • $\begingroup$ @kingledion: The same examples and at the same time! $\endgroup$
    – AlexP
    Commented Jan 16, 2017 at 16:36
  • $\begingroup$ Add that we have 4 astronomical events which mark the begin of each season: 2 equinoxes and 2 solstices. These can hardly be extended to 8. $\endgroup$
    – L.Dutch
    Commented Jan 17, 2017 at 11:43
  • $\begingroup$ @L.Dutch I'd like to point out that the convention of using these events as borders between seasons is not universal. I never heard of it until I was in my twenties, and I'm pretty sure I've only encountered the idea in English. In my native Scandinavia the summer solstice is known as midsummer, not "start-of-summer". You could use them as borders, but they are not canonical and there's nothing stopping you from adding more borders. Beyond the arctic circle, for instance, the beginning and end of the polar night and midnight sun constitute four additional, very natural astronomical events. $\endgroup$
    – EdvinW
    Commented Mar 5, 2022 at 6:46

Entire planets don't have the same seasons

Here is a climate data graph for Singapore. Singapore only has one season, hot and wet. The average monthly temperature is between 22.3 and 23.3 C every month, and there is always more than 160mm of rain.

But, obviously, there are seasons in other places on the Earth. The mid-latitudes have summer and winter; the savanna belts have wet and dry, there are monsoon seasons and not-monsoon seasons, etc.

A specific place can have four different types of weather

Chennai in India is a good example of four different types of weather. If you look at the climate graph here, there are several different seasons.

First there is the cool, dry season of Jan-March. Nighttime lows get to 20 C or below, the coolest of the year (cool is relative, I guess). Then there is the hot-dry of May-June. Daytime highs get well above 35 C. This suddenly breaks when the Southeast monsoon, or short rains arrive in Jul-Sep. The weather is rainy, but not too wet, and while average temps remain high, the daytime peaks are lower. Finally, the Northwest monsoon arrives bringing cooler weather and heavy rains from the Bay of Bengal. About half the yearly rainfall arrives in October and November with the long rains.

A good way to explain the residents considering there to be eight seasons is to make the year much longer. If the year is four times the length of an Earth year, then the transition between the short and long rains will take almost 120 days of variable weather, long enough to be deemed its own season.


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