Winter is often associated with plunging temperatures and icy weather, but its impact and timing changes according to location. Most people think the coldest season begins during the winter solstice, but there are in fact two definitions of winter. Let's take a look at this cool time of year.

<br> 	The above winter landscape of frosty trees and shrubbery is in Denmark, a <a href="">Scandinavian</a> country in Northern Europe. The days are short in Denmark during the winter, with sunsets occurring at about 3:45 p.m.

The above winter landscape of frosty trees and shrubbery is in Denmark, a Scandinavian country in Northern Europe. The days are short in Denmark during the winter, with sunsets occurring at about 3:45 p.m.
Credit: Dhoxax shutterstock

The coldest season of the year, winter comes between autumn and spring. The farther an area lies from the equator, the colder temperatures it experiences. Temperatures in equatorial regions stay relatively constant despite the shifting seasons. This is because, due to the curve of the Earth, the equatorial areas get more sunlight, according to the Atmospheric Radiation Measurement (ARM) program.

Most people refer to astronomical winter when they refer to the season. Ranging from the winter solstice to the vernal equinox, astronomical winter has to do with Earth's position around the sun. During the winter solstice — which falls around December 21 in the Northern Hemisphere and June 21 in the Southern Hemisphere, according to the National Weather Service (NWS) — the path that the sun travels in the sky reaches its lowest point. It is the shortest day of the year, and has been noted and celebrated by a wide variety of cultures around the world. [Gallery: Images of Stunning Snowy Landscapes]

During the winter solstice, the corresponding pole is tipped about 23.5 degrees away from the sun, according to the NWS. On that day in the Northern Hemisphere, the North Pole is farther from the heat-producing star, while the Southern Hemisphere, which experiences summer, is closer. 

But anyone who regularly engages in winter sports might tell you that winter weather tends to fall before the middle of December or June. Meteorological winter falls sooner, spanning the three-month period from December to March, according to NOAA. Based on weather such as snow and ice, meteorological winter doesn't rely on Earth's journey around the sun. While astronomical winter begins on the same date for the whole hemisphere, meteorological winter comes earlier for those farther from the equator.

Winter brings many changes to the world around it. During winter, some animals migrate, which means moving to another area for a season's time. Usually, animals go south to warmer areas during the winter. In response to global warming, some bird species now arrive in spring breeding grounds earlier, and lay eggs earlier, according to a report by the World Wildlife Fund (WWF). In Europe, some birds that normally migrate have stopped migrating altogether, according to the report. 

Species movement has to do with changes in habitat, as well, Keith Peterman, a professor of chemistry at York College of Pennsylvania, and Gregory Foy, an associate professor of chemistry at York College of Pennsylvania, explained to Live Science. Migration isn't just about staying warm. Animals can be forced out of their normal habitat because of changes in their food supply and introduction of new bacteria or viruses (due to the change in climate) where they have poor resistance.

Others animals begin a period of hibernation during the winter, passing much of the season in a near-sleep state. Because many plants die or are dormant, animals may stockpile food to help them through periods of want.

In addition to changing their locations and habits, some animals may also change their appearance. Animals such as hares and foxes may change their coloration to blend into snowy landscapes better. For example, the snowshoe hair is brown during warm months, but then turns white to blend in with the snow, according to National Geographic. Other animals might grow thicker fur to help them to stay warm.

Although winter tends to be a hard time for animals and humans alike, some winters host more extreme weather than others. Some of the extreme storms are listed below:

Ice floes on the Danube in Budapest, as seen on Feb. 11, 2012.
Ice floes on the Danube in Budapest, as seen on Feb. 11, 2012.
Credit: adambotond/flickr

Known as the Storm of the Century, a storm system that formed over the Gulf of Mexico in March of 1993 blanketed the Eastern United States with snowfall, scattered tornadoes and hurricane-force winds of up to 120 mph (193 km/h), according to the NOAA. The storm affected 26 states, with snow falling as far south as the usually sunny Jacksonville, Florida. Drifts piled up as high as 35 feet, and many Southern states, unprepared for the need for large-scale snow removal, shut down completely.

In February 2012, a deadly cold wave ravaged Europe, causing more than 800 deaths. Temperatures reached as low as minus 38.6 degrees Fahrenheit (minus 39.2 Celsius), and snow blanketed several countries, setting records for many of them. The second-longest river in Europe, the Danube, froze, as did the Venice canals. Northern Africa also felt the breath of the storm, with snow covering parts of the Sahara. More than 100,000 people were trapped by snow and ice.

In the winter of 1783, temperatures dropped significantly in Europe, reaching as low as 3.6 degrees F (2 degrees C).

In March 1888, a snowstorm blanketed the northeastern United States, from Maine down to Washington, D.C., with 55 inches (139.7 centimeters) of snow, according to History. Over four feet of snow dropped in Connecticut and Massachusetts, while New York and New Jersey boasted almost three and a half feet. The storm sank 200 ships and killed 400 people.

In November 1940, a blizzard quickly plunged temperatures from 60 degrees down to single digits, according to the Star Tribune. Winds of up to 80 mph (129 km/h) pushed snow into 20-foot drifts across the Midwest. The surprise weather change ended up claiming many lives.

Antarctica currently boasts the lowest temperature on record. On July 21, 1983, temperatures at the Russian station, Vostok, reached minus 128.6 degrees F (minus 89 C). The coldest place on Earth during the winter is Antarctica's East Antarctic Plateau where temperatures can drop below minus 133.6 degrees F (minus 92 degrees C), according to NASA. Canada's lowest temperature was recorded Feb. 3, 1947, at minus 81 F (minus 63 C), while temperatures in the United States reached minus 79.8 F (minus 62 C) in northern Alaska on Jan. 23, 1971.

Historically, the Little Ice Age is probably the most memorable period of extreme cold. It spanned a number of years, roughly from 1275 to 1300, bringing extremely cold temperatures to Europe and North America. Large rivers, including the Thames in England, froze completely. A number of causes for the surprising drop in temperature have been proposed, including changes in solar and volcanic activity.

Cold winters can quickly bring on life-threatening medical conditions, such as hypothermia. Hypothermia is when a human's body temperature drops below 95 F (35 C), according to the Mayo Clinic. Cold temperatures and wind chill can make a person's body temperature drop in just minutes. 

The cold temperatures can also cause frostbite, the freezing of skin and tissue. Cold temperatures are just one factor when it comes to frostbite susceptibility. "Other factors also come into play including the age/size of the individual (e.g., quicker onset in small children) or if an individual has less than optimal circulation to distal body parts such as hands/finger/feet/toes. Such pre-existing conditions might include diabetes, autoimmune vascular disorders, or atherosclerosis obliterans (hardening of the arteries)," said Dr. Nicholas Lorenzo, the chief medical officer with MeMD, a Web-based health services provider. 

To avoid hypothermia and frostbite, it is important to keep all skin covered and dry during cold weather. Once a person has hypothermia or frostbite, the primary treatment is rewarming the patient.

A famous painting from 1677, The Frozen Thames, shows the enormous river in England frozen solid during the Little Ice Age.
A famous painting from 1677, The Frozen Thames, shows the enormous river in England frozen solid during the Little Ice Age.
Credit: Public domain

"Laughter is the sun that drives winter from the human face."
— Victor Hugo

"Now is the winter of our discontent."
— William Shakespeare

“If winter comes, can spring be far behind?”
― Percy Bysshe Shelley

“Winter is not a season, it's an occupation.”
― Sinclair Lewis

“Winter is the time for comfort, for good food and warmth, for the touch of a friendly hand and for a talk beside the fire: it is the time for home.”
― Edith Sitwell

"You can't get too much winter in the winter."
— Robert Frost

“Winter is nature's way of saying, 'Up yours.'”
― Robert Byrne

“What good is the warmth of summer, without the cold of winter to give it sweetness.”
― John Steinbeck

“Melancholy were the sounds on a winter's night.”
― Virginia Woolf

"I had slumps that lasted into the winter."
— Bob Uecker

Additional reporting by Alina Bradford, Live Science contributor.

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