50 Fun Facts About Seasons

What is the primary cause of Earth's seasons?

The axis is tilted about 23.4 degrees to the orbital plane and keeps pointing toward Polaris all year, so each hemisphere takes turns leaning toward the Sun.

By roughly how much is Earth's axis tilted relative to its orbital plane?

Astronomers call it the obliquity of the ecliptic. It wobbles between 22.1 and 24.5 degrees over a 41,000-year cycle, one of the Milankovitch cycles that pace ice ages.

In which month is Earth closest to the Sun?

Perihelion falls in early January and aphelion in July, so distance actually works against the Northern Hemisphere's seasons. The difference in sunlight is only about 7 percent.

Why is Earth as a whole slightly warmer when it is farthest from the Sun?

Northern summer coincides with aphelion, and land heats up more readily than sea, so the planet's average temperature ticks up despite the extra distance.

The word 'solstice' comes from Latin words meaning what?

At the solstices the Sun's daily path reaches its northern or southern limit and appears to pause before reversing. A rare English calque, 'sunstay,' dates from the 16th century.

'Equinox' comes from Latin words meaning what?

At the two equinoxes the Sun is directly overhead at the Equator and both poles sit on the terminator, so day and night are split evenly between the hemispheres.

Around what date does the Northern Hemisphere tip most toward the Sun?

That is the June solstice, the longest day north of the Equator. The Southern Hemisphere's maximum comes around December 21.

Why are July and August, not June, usually the hottest months in the Northern Hemisphere?

The most direct sunlight arrives in May, June and July, but the oceans take weeks to warm, so temperatures peak after the solstice.

Under meteorological reckoning, on what date does spring begin in the Northern Hemisphere?

Meteorologists split the year into four three-month blocks starting March 1, June 1, September 1 and December 1. Australia and Russia prefer this system.

On the traditional Celtic calendar, which festival on November 1 marked the start of the coldest season?

Imbolc opened spring on February 1, Beltane summer on May 1 and Lughnasadh autumn on August 1. Samhain is the Celtic root of Halloween.

How many seasons, or ritus, does the traditional Hindu calendar recognize?

They are Vasanta, Grishma, Varsha (monsoon), Sharada, Hemanta and Shishira. Some Aboriginal Australian peoples and the Sami count up to eight.

The ancient Egyptian year had three seasons defined by what?

They were flood, growth and low water. Many tropical regions today still count just two seasons, wet and dry.

Ecologists sometimes use a six-season model for temperate regions. Which of these is one of its seasons?

The six are prevernal, vernal, estival, serotinal, autumnal and hibernal, keyed to biological events rather than calendar dates.

Which of Earth's polar regions is consistently colder during its dark season, and why?

The North Pole floats on the Arctic Ocean, whose water buffers its temperature extremes.

Before the 16th century, what word was commonly used in English for the season we now call autumn?

Other West Germanic languages still use their version of it. 'Fall' comes from old Germanic roots and survives mainly in North American English.

The yellow and orange colors of autumn leaves come from which pigments?

Xanthophylls and beta-carotene are in the leaf all summer, hidden by chlorophyll's green. Reds, by contrast, come from anthocyanins made fresh in autumn.

Which pigment gives autumn leaves their red color?

Unlike the yellows, it is produced only as the leaf's sugar breakdown changes in autumn. Brown leaves come from green and red pigments combining as cells die.

Which full moon is the one farmers traditionally named for bringing in the crops?

Also called the barley moon or full corn moon, it can fall up to two weeks either side of September 22 or 23.

What is an 'Indian summer'?

The term's origin is uncertain; it may refer to the hazy autumn hunting weather in regions inhabited by Native Americans.

The 'dog days' of summer were named for the rising of which star?

Hellenistic astrology blamed the Dog Star for heat, drought, lethargy, fever and mad dogs. The Greeks called it Seirios, the Scorcher.

On what date is Groundhog Day observed?

It descends from Candlemas lore, and a German tradition called the same day 'Badger Day.' Punxsutawney Phil saw his shadow in 2026, promising six more weeks of winter.

In the German tradition before Groundhog Day, which animal's Candlemas shadow predicted four more weeks of cold?

Pennsylvania German settlers swapped in the groundhog and stretched the forecast to six weeks.

Midsummer celebrations were Christianized as the June 24 feast of which biblical figure?

In Anglo-Saxon England summer began on May 9 and peaked at Midsummer on June 24. Sweden treats the holiday so seriously there have been proposals to make it the National Day.

In Greek myth, Hades tricked Persephone into eating what, binding her to the underworld?

Her mother Demeter's grief while she is below was the ancient explanation for winter, and her return brought spring.

Stonehenge is aligned toward the sunrise on which day?

The same axis points to sunset on the winter solstice. Warren Field in Aberdeenshire, corrected each midwinter, is considered the world's oldest lunisolar calendar.

Each concerto in Vivaldi's Four Seasons is paired with what kind of poem?

Each concerto has three fast-slow-fast movements and each poem breaks into three matching sections, which is why many think Vivaldi wrote the poems himself.

In what year were Vivaldi's Four Seasons published?

They appeared as part of Il cimento dell'armonia e dell'inventione, The Contest Between Harmony and Invention. A 2019 'recomposition' called For Seasons used algorithms to portray climate change.

Frankie Valli's group The Four Seasons took its name from what?

They failed an audition for the lounge at a New Jersey bowling establishment in 1960 and kept the name anyway. 'Sherry' became their first number one in 1962.

Which of these was a number one single for The Four Seasons?

Bob Gaudio wrote it, and it was followed to number one by 'Big Girls Don't Cry,' 'Walk Like a Man,' 'Rag Doll' and, in 1976, 'December, 1963 (Oh, What a Night).'

Haydn's oratorio The Seasons, first performed in 1801, is based on a long English poem by whom?

Thomson's The Seasons was published in 1730. Baron van Swieten adapted it so freely that scholars say the libretto often loses touch with the poem.

On Uranus, tilted almost 98 degrees, roughly how long does each pole spend in continuous sunlight?

Its orbit takes 84 Earth years, so each pole gets about 42 years of daylight followed by 42 years of dark, the most extreme seasons in the solar system.

The midnight sun occurs in summer beyond which lines of latitude?

Because of refraction it can be seen from about 65 degrees 44 minutes, slightly outside the Arctic and Antarctic circles.

What is the Japanese custom of viewing cherry blossoms in spring called?

Cherry trees bloom across Japan from late March to early May, but on Okinawa the season starts around the second week of January.

Which Southern Hemisphere country uses meteorological reckoning, so summer officially begins December 1?

Australia, New Zealand, Pakistan and Russia are among the countries that prefer meteorological reckoning over solstices and equinoxes.

How much does the amount of sunlight Earth receives vary between perihelion and aphelion?

That small swing is swamped by the effect of axial tilt, and it is partly cancelled out by the Southern Hemisphere's abundance of ocean.

Which people of Scandinavia traditionally recognize up to eight seasons?

Their calendar tracks reindeer herding, with seasons like spring-winter and autumn-summer between the main four.

How much earlier do Celtic cross-quarter seasons start than equinox-and-solstice seasons?

They also start three to four weeks before the meteorological seasons, treating the solstices and equinoxes as midpoints rather than beginnings.

Earth's axis keeps pointing toward which star all year, a property called axial parallelism?

The axis does wobble, but the precession cycle takes about 26,000 years, so it is invisible to human civilization.

Roughly how long is Earth's axial precession cycle?

Over that period the axis traces a slow circle, so thousands of years from now a different star will serve as the pole star.

Which season is defined as the coldest and darkest of the year in temperate and polar climates?

At the winter solstice the Sun sits at its farthest below the horizon as measured from the pole, and inside the polar circles it does not rise at all.

At the spring equinox, roughly how long are day and night?

From then until the summer solstice, days lengthen and nights shrink. The astronomical vernal equinox falls between March 19 and 21.

Which astronomer showed that the astronomical seasons are unequal in length because Earth's orbit is an ellipse?

March equinox to September equinox currently runs 7.56 days longer than the other half of the year.

How many climatological seasons does the India Meteorological Department designate?

They are winter, the pre-monsoon summer, the monsoon from June to September, and a post-monsoon autumn in October and November.

The traditional Chinese calendar divides its four seasons into how many 'solar terms'?

Half are called zhōngqi and half jiéqi; spring is said to begin at Lichun, around 4 February.

In Nicaragua, the dry season from November to April is popularly called what?

The rainy season from May to October is called 'winter', even though the country lies in the Northern Hemisphere.

How many seasons do the Noongar people of South-West Western Australia recognise?

Each maar-keyen bonar season is heralded by winds, flowering plants and migration patterns rather than a calendar date, and lasts about two months.

In Sweden and Finland's thermal seasons, spring begins when the mean daily temperature permanently rises above what?

Summer starts above +10 °C and winter below 0 °C; Finland defines 'permanently' as seven consecutive days.

Who was the Roman god of the seasons?

Roman writers such as Varro were already using the four-season model, starting spring on 7 February.

On which date did the Roman scholar Varro place the start of spring, after Caesar's calendar reform?

His seasons began on the 23rd day of the Sun's passage through Aquarius, Taurus, Leo and Scorpio: 7 February, 9 May, 11 August and 10 November.

Which 1780 body first defined meteorological seasons as groupings of three whole calendar months?

The early international meteorological organisation was defunct by 1795, but its convention of March 1, June 1, September 1 and December 1 survives.