Winter is one of the four seasons of temperate zones. Calculated astronomically, it begins on the solstice and ends on the equinox. It is the season with the shortest days and the lowest average temperatures. It has colder weather and, especially in the higher latitudes or altitudes, snow and ice. The coldest average temperatures of the season are typically experienced in January in the Northern Hemisphere and in July in the Southern Hemisphere.
Meteorological winter is the season having the shortest days and the lowest temperatures. Night-time predominates the winter season, and in some regions it has the highest rate of precipitation as well as prolonged dampness because of permanent snow cover or high precipitation rates coupled with low temperatures, precluding evaporation. Blizzards often develop and cause many transportation delays. A rare meteorological phenomenon encountered during winter is ice fog, which is composed of ice crystals suspended in the air and happening only at very low temperatures, below about −30 °C
Accumulations of snow and ice are mostly associated with winter in the Northern Hemisphere, due to the large land masses there. In the Southern Hemisphere, the more maritime climate and the relative lack of land south of 40 degrees South makes the winters more mild, and thus snow and ice are less common in inhabited regions of the Southern Hemisphere. In the Southern Hemisphere, snow occurs every year in elevated regions such as the Andes, the Great Dividing Range in Australia, and the mountains of New Zealand, and also occurs in the southerly Patagonia region of South America. Snow occurs year-round in Antarctica.
Astronomically, winter starts with the winter solstice
and ends with the vernal equinox
. Others consider the seasons to be defined by weather, winter being approximately the whole months of June, July and August in the Southern Hemisphere
in the Northern Hemisphere
. By still another definition, the seasons are spoken of, not as quarters of the year, but elastic periods in a particular place determined by the weather, winter in that reckoning being when the weather turns decidedly cold.
In Celtic nations such as Ireland using the Irish calendar, the winter solstice is traditionally considered as midwinter, with the winter season beginning November 1 on All Hallows or Samhain. Winter ends and spring begins on Imbolc or Candlemas, which is February 1 or February 2. This system of seasons is based on the length of days exclusively. The three-month period of the shortest days and weakest solar radiation occurs during November, December and January in the Northern Hemisphere and May-July in the Southern Hemisphere.
Also many mainland European countries tend to recognize Martinmas, St. Martin's day (November 11) as the first calendar day of winter. The day falls at midpoint between the old Julian equinox and solstice dates. Also, Valentines Day (February 14) is recognized by some countries as heralding the first rites of Spring (season), such as flower blooming.
In Chinese astronomy (and other East Asian calendars), winter is taken to commence on or around November 7, with the Jiéqì known as (立冬 lì dōng, literally "establishment of winter".)
The three-month period associated with the coldest average temperatures typically begins somewhere in late November or early December in the Northern Hemisphere. If "winter" is defined as the statistically coldest quarter of the year, then the astronomical definition is too late by almost all local climate standards, and the traditional English/Irish definition of November 1 (May 1 in the Southern Hemisphere) is usually too early to fit this standard. No matter the reckoning, winter is the only season that spans two calendar years in the northern hemisphere. (In other words, there are very few temperate climates in which the vernal equinox is on average colder than the winter solstice, and very few temperate climates in which Samhain is colder than Imbolc).
The tilt of the Earth
's axis relative to its orbital plane has a dramatic effect on the weather. The Earth is tilted at an angle of 23.44° to the plane of its orbit, and this causes different latitudes on the Earth to directly face the Sun
as the Earth moves through its orbit. It is this variation that primarily brings about the seasons. When it is winter in the Northern Hemisphere, the Southern Hemisphere faces the Sun more directly and thus experiences warmer temperatures than the Northern Hemisphere. Conversely, winter in the Southern Hemisphere occurs when the Northern hemisphere is tilted more toward the Sun. From the perspective of an observer on the Earth, the winter Sun has a lower maximum altitude in the sky than the summer Sun.
During winter in either hemisphere, the lower altitude of the Sun in winter causes the sunlight to hit that hemisphere at an oblique angle. In regions experiencing winter, the same amount of solar radiation is spread out over a larger area. This effect is compounded by the larger distance that the light must travel through the atmosphere, allowing the atmosphere to dissipate more heat.
To survive the harshness of winter, many animals have developed different behavioral and morphological adaptations for Overwintering:
- Migration is a common effect of winter upon animals, notably birds. However the majority of birds do not migrate, the cardinal or European Robin for example. Some butterflies also migrate seasonally.
- Hibernation is a state of reduced metabolic activity during the winter. Some animals "sleep" during winter and only come out as warm weather returns. For example, [(animal)|gopher]s, bears, frogs, snakes and bats hibernate.
- Some animals store food for the winter and live upon it instead of hibernating completely. This is the case of squirrels, beavers, skunks, badgers and raccoons.
- Resistance is observed when an animal endures winter but changes in ways such as color and musculature. The color of the fur or plumage are changed to white in order to be confused with snow and thus, to retain their cryptic coloration year round. Examples are the ptarmigan, the arctic fox, the weasel, the white-tailed jack rabbit or the mountain hare.
- Some fur-coated mammals grow a heavier fur coat during the winter. This improves the heat-retention qualities of the fur. The coat is then shed following the winter season to allow better cooling. The heavier winter coat made this season a favorite for trappers who sought more profitable skins.
- Snow also affects the ways animals behave; many take advantage of the insulating properties of snow by burrowing in it. Mice and voles typically live under the snow layer.
Annual plants never survive the winter. As for perennial plants, many small ones profit from the insulating effects of snow by being buried in it. Larger plants, particularly deciduous trees, usually let their upper part go dormant, but their roots are still protected by the snow layer. Few plants bloom in the winter, with exceptions including the flowering plum (which flowers in time for Chinese New Year).
Many winter activities involve the use of snow in some form (which sometimes may still be manmade, via snow cannons):
- Bobsledding - a winter sport in which teams make timed runs down narrow, twisting, banked purpose-built iced tracks in a gravity-powered, steerable sled.
- Skiing - the activity of gliding over snow using fiberglass planks called skis that are strapped to the skiers' feet with ski bindings.
- Sledding - a downhill activity using a sled to glide downhill.
- Snowball fight - a physical game in which snowballs are thrown with the intention of hitting someone else.
- Snowboarding - an increasingly common sport where participants strap a composite board to their feet and slide down a snow-covered mountain.
- Snowshoeing - a means of travel on top of the snow by increasing the surface area of the feet.
- Snowman building - creating a man-like model out of snow.
- Snow castle building - for example constructions such as the SnowCastle of Kemi, the largest in the world.
Many other winter activities and sports focus on ice, which may be contained in an ice rink.
- Ice skating - a means of traveling on ice with skates, narrow (and sometimes parabolic) blade-like devices molded into special boots.
- Ice boating - a means of travel in a specialized boat similar in appearance to a sailboat but fitted with skis or runners (skates) and designed to run over ice instead of (liquid) water.
- Ice biking - The continuation of regular cycling activities in the winter and cold weather.
- Ice fishing - the sport of catching fish with lines and hooks through an opening in the ice on a frozen body of water.
- Ice diving - a type of penetration diving where the dive takes place under ice.
- Ice sculpture - elaborate sculptures are carved out of blocks of ice.
- Ice Hockey - A team sport played on the ice with skates, sticks and a puck. The goal is to send the puck in the adversary team's net.
- Curling - A team sport using brooms and stones. The object of the game is to slide your stones in a bullseye and get your opponent's stones out of it.
- Ice climbing - The recreational activity of climbing ice formations such as icefalls and frozen waterfalls.
Passing seasons change the habits and moods of people. During the winter months in the northern hemisphere, a gloominess nicknamed "winter blues", "February blahs", "Holiday depression", or doldrums, is informally noted amongst people. The severest cases of this type of depression
is diagnosed as seasonal affective disorder
(SAD). Symptoms include sleeping more, tiredness, depression, and physical aches. Although causes include genetic disposition and stress, the prevailing environmental influence is decreased exposure to light
because of the angle of the sun and cloudcover and the increased amount of clothing that must be worn to keep warm.
Some use winter to suggest death, as in Robert Frost
's "Stopping by Woods on a Snowy Evening
". Some use it to suggest the absence of hope, as in C. S. Lewis
's The Lion, the Witch and the Wardrobe,
where it was always winter but never Christmas
. Winter is one concerto in Antonio Vivaldi
's "The Four Seasons"; and there are many examples of four paintings, all showing the same scene in different seasons. Ursula K. LeGuin's novel The Left Hand of Darkness
is set on a planet named Winter. In Alex Raymond
's comic strip, Flash Gordon
, there is a land called Frigia, where it is always winter. The land of Frigia is also featured in the serial Flash Gordon Conquers the Universe
. Other uses of winter in the graphic arts occur in Winsor McCay
's Little Nemo in Slumberland
. There are many films in which a winter setting plays an important role, Fargo
being an example. Novels such as Ethan Frome
also use a winter setting to mirror the bleak, frozen feelings that the characters harbor. The film Requiem for a Dream
concludes with "Act III: Winter", in which the movie reaches its hellish and chilling climax.
In various cultures
In Greek mythology
to be his wife. Zeus
ordered Hades to return her to Demeter
, the goddess of the earth and her mother. However, Hades tricked Persephone into eating the food of the dead so Zeus decreed Persephone would spend six months with Demeter and six months with Hades. During the time when her daughter is with Hades, Demeter becomes depressed and causes winter. In Welsh Mythology
, Gwyn ap Nudd
abducted a maiden named Creiddylad
. On May Day
her lover Gwythr ap Greidawl
fought Gwyn to win her back. The battle between them represented the contest between summer and winter.
- Rosenthal, Norman E. (1998). Winter Blues. New York: The Guilford Press. ISBN 1-57230-395-6