Winter

Seasons

Temperate
Spring
Summer
Autumn
Winter
Tropical
Dry season
Wet season

Winter is one of the four seasons of temperate zones. It is the season with the shortest days and the lowest temperatures. In areas farther from the equator, winter is often marked by snow.

Depending on place and culture, what is considered to be the start and end of winter vary. Contemporary meteorology takes winter to be the months of December, January, and February in the Northern Hemisphere and June, July, and August in the Southern Hemisphere. However, many cultures in Europe and East Asia consider winter to begin in November.

Meteorological aspects

Meteorological winter is the season having the shortest days (which vary greatly according to latitude) and the lowest temperatures. Nighttime predominates the winter season, and in some regions it has the highest rate of precipitation as well as prolonged dampness due to permanent snow cover in such areas. Measured astronomically, winter begins on the shortest day of the year, and each day of winter has more sunlight than the previous one.

Outside the equatorial areas, winter is cold and (particularly in the Northern Hemisphere) snowy. 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 (at least 10 degrees below zero Fahrenheit).

Time period of winter

Astronomically, it starts with the winter solstice (around December 21 in the Northern Hemisphere and June 21 in the Southern Hemisphere), and ends with the spring equinox (around March 21 in the Northern Hemisphere and September 23 in the Southern Hemisphere). In meteorology, it is by convention counted instead as the whole months of June, July and August in the Southern Hemisphere and December, January and February in the Northern Hemisphere.

However, in the United Kingdom and Ireland the winter solstice is traditionally considered as midwinter, the winter season beginning November 1 on All Hallows or Samhain. Elsewhere, in Chinese astronomy (and other East Asian calenders), winter is taken to commence on or around November 7, with the Jiéqì known as (立冬 lì dōng, literally "establishment of winter".)

What causes winter

Our planet is tilted on its axis, and this has a dramatic effect on the weather. The popular belief that winter is caused by the Earth moving away from the Sun in its orbit is not true. For example, winter occurs in the Northern Hemisphere when the Earth is closest to the Sun.

The planet is tilted at an angle of 23°27' (23 degrees 27 minutes) 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.

During winter in either hemisphere, the radiation from the Sun hits that hemisphere at an oblique angle. In regions experiencing winter, the same amount of solar radiation is spread out over a larger area. See how directness of sunlight causes warmer weather. This effect is compounded by the larger distance that the light must travel through the atmosphere, allowing the atmosphere to filter more of this already limited heat.

Activities

Main article: Winter sport

Snow activities

• 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 what is now fiberglass planks called skis that are strapped to the skiers' feet with ski bindings.

• Sledding - a downhill activity where the user uses a sled to glide down the hill.
• 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 in which one is able to walk on top of the snow by increasing the surface area of their feet.
• Snowman building - creating a man-like model out of snow

Ice activities

• Ice Skating - a means of traveling on ice with skates, narrow (and sometimes parabolic) blade-like devices moulded into special boots (or, more primitively, without boots, tied to regular footwear).
• 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 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.

Ecology

Animals

To survive the harshness of winter, many animals have developed different behavioral and morphological adaptations:

• Migration is a common effect of winter upon animals, affecting basically birds. However some birds, i.e. the cardinal do not migrate.
• Hibernation is a state of reduced metabolic activity during the winter. These animals "sleep" during winter and only come out as warm weather returns. For example, gophers, bears, frogs, snakes or 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 colour and musculature. The colour 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, as many take advantage of the insulating properties of snow by burrowing in it. Mice and voles typically live under the snow layer.

Plants

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 die, but their roots are still protected by the snow layer.Few plants bloom in the winter, though exceptions include the flowering apricot (which flowers in time for Chinese New Year).

Psychology

Passing seasons change the habits and moods of people. Around winter months, a gloominess, called "winter blues" or "February blahs" or "Holiday depression"-- during November and December in the northern hemisphere-- 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 due to winter weather patterns.

The symbolism of winter

Winter is highly symbolic of many things to many people and has been used to represent various things by artists in all media. Some use winter to suggest death, as in Robert Frost's "Stopping by the 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 movement in 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. In addition to this, novels such as Ethan Frome also use a winter setting to mirror the bleak, frozen feelings that the characters harbor.

Mythological explanations of winter

In Greek mythology, Hades kidnapped Persephone 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 decreeded 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.

Exceptional winters

• Russian Winters of 1812/13 and 1941/42
• The Winter of Discontent is the name for the British winter of 1978-79, during which there were widespread strikes. Lorry drivers, train drivers, nurses, most public sector employees, refuse collectors, and workers at Ford Motors all went on strike. Most notorious however was an unofficial strike by gravediggers.