Micro-Season: “The Sky is Cold, Winter Comes”

We have entered the micro-season of “The Sky is Cold, Winter Comes”.  This is the first micro-season of the mini-season Major Snow.  All the micro-seasons within Major Snow are:

• The Sky is Cold, Winter Comes (Dec.07 -Dec. 11)
• The Bear Retreats to its Den (Dec. 12 -Dec 16)
• The Salmon Gather to Spawn (Dec. 17 -Dec 21)

These seasons were established in 1685 by Japanese astronomer Shibukawa Shunkai and are specific to Japan. However, just because the calendar focuses on Japan doesn’t mean it isn’t applicable to others.  No matter where you live you can use these seasons as a starting point for your personal exploration of the world around you. 

To celebrate this season, we will learn about how the Earth’s orbit around the Sun impacts our seasonal temperatures. Then we will read some seasonal haiku by Buson, Issa, Basho, Taigi, and Toshimi.

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“The Sky is Cold, Winter Comes” marks the middle of the winter seasons in the 72-season calendar.  This is also the time of year when those of us in the northern hemisphere begin to notice a drop in outside temperature.  This drop in temperature is due to a variety of factors related to the Earth’s orientation to the Sun.

How Does The Sun Heat The Earth?

The Sun produces a lot of energy.  Scientists call the energy produced by the Sun “Solar Radiation”.  The earth absorbs about “240 watts of solar power per square meter (one watt is one joule of energy every second).”⁽¹⁾ This energy drives a variety of processes on Earth including the warming of the Earth’s surface.  

The Earth’s surface temperature is regulated by incoming and outgoing energy. During the daylight hours, the earth receives more energy from the Sun than it is losing through things like convection. Convection is the “process by which heat is transferred by movement of a heated fluid such as air or water.”⁽²⁾  

During the evening hours, the earth loses more energy than it receives.  This loss of energy results in a drop in atmospheric temperatures.  

How Does the Earth’s Orbit and Tilt Influence Temperature?

The Earth travels around the Sun in an elliptical orbit.  The Earth also spins on its axis while traveling in its orbit.  Because the Earth rotates around its fixed axis of 23.5 degrees different parts of the Earth receive different amounts of sunlight.  

What this means is that in December the North Pole is titled away from the sun. Therefore, the northern parts of the Earth get less direct sunlight.  This is directly opposite to the position of the North Pole in June. In June, the North Pole is titled towards the sun and the northern hemisphere gets more sunlight.⁽³⁾

The illustration below from NOAA SciJinks page does a wonderful job of illustrating this point.

As the Earth travels around the Sun, and we approach the winter solstice (December 21, 2022), the days get shorter.  The shorter days mean there is less time for the sun to warm the earth and more time for the earth to lose its heat.  This will therefore result in a drop in temperature. 

How Does Latitude Influence Temperature?

Your location on the Earth greatly influences your seasonal temperatures.  This is because the angle at which the Sun’s rays hit the Earth impacts the temperature. At higher latitudes, (farther away from the equator), the energy you receive from the Sun is more dispersed.  However, if you live on the equator, the energy you receive from the Sun’s rays is more concentrated.  

Climate scientists will also point out “Because the angle of radiation varies depending on the latitude, surface temperatures on average are warmer at lower latitudes and cooler at higher latitudes (even though higher latitudes have more hours of daylight during the summer months).”⁽⁴⁾

Other Factors That Influence Seasonal Temperatures

Besides the intensity of the Sun’s rays, the tilt of the Earth, and where the Earth is in its orbit around the Sun, there are still other factors that influence seasonal temperatures including altitude and large bodies of water.  

Altitude: Temperature decreases as you travel higher in altitude.  It is said “For every 100-meter increase in elevation, the average temperature decreases by 0.7°C.”⁽⁵⁾

Water: Large bodies of water influence temperature because they have a high heat capacity.  What this means is that they take longer to warm and cool than dry land.  Because of this, areas near large bodies of water tend to have more moderate temperatures.⁽⁶⁾

Seasonal Haiku

At this time of year, things are getting colder. The World Kigo Database tells us that “Cold” is not actually a kigo, but it is a topic for haiku.⁽⁷⁾ This makes sense when you think about it.  You can use the term “cold” in a variety of ways.  For example, you can have a “cold spring morning”, or “cold soup”, or a “cold smile”.  

In order to place “cold” directly in winter, you could say things like “cold winter evening”, “cold winter night”, or “cold winter morning”.  However, there does seem to be a slight exception to this formula. That exception is “Cold Moon”. 

“Cold Moon” or kan no tsuki is a winter kigo.⁽⁸⁾ There are other slight variations of “Cold Moon” including “winter moon”, “freezing moon”, and “moon in the cold” which are also winter kigo. 

With all this in mind, let’s read some seasonal haiku that focus on the Cold Moon and its variations.

Buson

this cold moon -
among the bare trees
three stalks of bamboo
(retrieved from World Kigo Database)

this cold moon -
fallen needles of pines
shoot into stones
(retrieved from World Kigo Database)

Tan Taigi

moon in the cold -
only my own footsteps
on the bridge
(translated by Dr. Gabi Greve)

Issa

like he's biting
the cold moon...
gargoyle
(translated by David G. Lanoue)

cold moon--
the blind priest is called
by mistake
(translated by David G. Lanoue)

a cold moon
facing the cold
mountain temple
(translated by David G. Lanoue)

Basho

the snow and snow.
this evening would have
the great moon of December
(retrieved from Masterpiece of Japanese Culture)

Horiuchi Toshimi

glittering flakes:
the wind is breaking
frozen moonlight.
(retrieved from JapanPowered)

A Haiku Invitation

This week’s haiku invitation is to write a haiku or senryu that references Cold Moon, Cold Sky, or a variation of this.

Share your haiku in the comments below, or post on your own page and link back to this post. I can’t wait to read what you write!  

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Resources

1. “Solar Radiation and the Earth’s Energy Balance”; Dawn Wells: Columbia University.
2. Convection; Brittanica.com
3. “Why Does Earth Have Seasons”; Scijinks
4. “Angle of Solar Radiation and Temperature” Climate Science Investigations- South Florida
5. “Elevation”; Climate Science Investigations-South Florida
6. “Water’s Influence on Temperature”; Climate Science Investigations-South Florida
7. “Cool, Cold, Chilly” World Kigo Database
8. “Moon and its related links”; World Kigo Database

Buson’s and Tan Taigi’s haiku were retrieved from the World Kigo Database.  Issa’s haiku were retrieved from David G. Lanoue’s Haiku Guy.  Basho’s haiku was retrieved from Masterpieces of Japanese Culture.  Horiuchi Toshimi haiku was retrieved from JapanPowered.com.