Winter

Winter is the coldest and darkest season of the year in temperate and polar climates. It happens after autumn and before spring, when the hemisphere is turned away from the Sun because of the tilt of Earth's axis. Different places and cultures may pick different dates to mark the beginning of winter, sometimes using weather patterns to decide.

When it is winter in the Northern Hemisphere, it is summer in the Southern Hemisphere, and the opposite is also true. Winter usually brings precipitation, which can be rain or snow depending on where you live. The winter solstice is a special moment when the Sun is at its farthest below the horizon, giving us the shortest day and longest night of the year. After the solstice, days slowly grow longer and nights shorter.

The earliest sunset and latest sunrise do not always happen on the same day as the winter solstice. This is because of how Earth's orbit around the Sun changes the length of each solar day throughout the year.

Etymology

The English word winter comes from an old language called Proto-Germanic, specifically from a word that sounds like wintru-. We don't know exactly where this word came from, but one idea is that it might be related to an even older language called Proto-Indo-European. In that language, there was a root word that means 'water' or something similar.

Cause

See also: Effect of Sun angle on climate

The Earth's tilt causes the seasons. When one part of the Earth is tilted away from the Sun, it experiences winter, while the other part is tilted toward the Sun and has warmer weather. During winter, the Sun is lower in the sky, so its light hits the Earth at an angle. This means less warmth reaches the ground, and the light has to pass through more air, which also cools it down.

Different places can have very different winter temperatures even if they are at the same latitude. For example, Winnipeg in the Great Plains area of Canada can be very cold, while Vancouver on the west coast stays much milder because of the nearby ocean and winds.

Timing

Meteorological reckoning

Further information: Meteorological seasons

Meteorological winter is measured by meteorologists using weather patterns for record-keeping. Winter starts differently depending on where you live, but it is often the three months with the lowest average temperatures. In the Northern Hemisphere, this is December, January, and February. In the Southern Hemisphere, it is June, July, and August.

The coldest temperatures usually happen in January or February in the north and in June, July, or August in the south. Nights are longer during winter, and some places get a lot of snow or rain because of the cold weather. Blizzards can happen, causing delays for cars and trains. Special ice crystals called diamond dust can form when it gets very cold.

Cultural reckoning

Ancient cultures often split the year into just two seasons: winter and summer. In the old Roman world, winter started on November 10 and ended on February 6. In England, winter began on November 7 and ended on February 6. Many European countries started winter on November 11. In Celtic nations, winter started on November 1 and ended on February 1. In Scandinavia, winter could start as early as October 14 and end at the end of February. In China, winter starts around November 7 and ends in early February.

In the Southern Hemisphere, including Australia, New Zealand, and South Africa, winter runs from June 1 to August 31.

Astronomical reckoning

Astronomical winter is based on Earth’s position around the Sun. One way to look at it is that winter starts on the winter solstice, the shortest day of the year, and ends on the March equinox. The coldest weather usually comes a few weeks after the solstice.

Ecological reckoning and activity

Winter is a special time for plants and animals, and many change their behavior to survive the cold. Ecologists call this time of year "hibernal," and it is when most plants and animals become less active.

Animals have many ways to get through winter. Some, like migratory birds and butterflies, travel to warmer places. Others, such as bears, frogs, and bats, enter a state called hibernation, where their bodies slow down a lot. Some animals, like squirrels and beavers, save food during the warmer months to eat during winter. Other animals change their fur color to blend in with the snow, like the Arctic fox. Many small animals live under the snow for protection.

Plants also have their own ways to handle winter. Some small plants stay safe under the snow, while bigger plants like trees rest above ground but keep their roots warm beneath the snow. Only a few plants, such as the flowering plum, bloom during winter.

Examples

Some winters have been unusually cold and have affected many places.

In the winter of 1683–1684, the River Thames in London froze thickly, allowing people to walk across it. The winter of 1816, called the "Year Without a Summer," was very cold because of a big volcano eruption that changed the weather worldwide. In 1888, strong blizzards hit parts of the United States and Canada.

Other notable cold winters include 1947 in the United Kingdom, 1956 in Europe, and 2013–2014 in the eastern United States and Canada. These winters brought a lot of snow and very low temperatures, making life difficult for many people.

Effect on humans

Winter cold can make it hard for our bodies to stay warm, which can lead to some health problems. Slippery ice can cause falls and injuries. The cold can also cause issues like hypothermia, where the body gets too cold and starts shaking, making it hard to move properly. Another problem is frostbite, where skin freezes and can get damaged. There are also conditions like trench foot, where feet become numb and tissue can be harmed, and chilblains, which affect small blood vessels and can lead to more serious cold injuries.

During winter, people also get sick more often with illnesses like influenza and COVID-19, as well as other breathing problems. It's important to stay warm and look after ourselves during this season.

Mythology

In Persian culture, the winter solstice is called Yaldā, meaning "birth," and has been celebrated for thousands of years. It marks the eve of the birth of Mithra, a symbol of light, goodness, and strength on Earth.

In Greek mythology, the story explains winter as a result of the goddess Demeter feeling sad when her daughter Persephone is away. Hades took Persephone to live with him, and she eats food that binds her to him. So, she spends half the year with Demeter and half with Hades. When Persephone is away, Demeter’s sadness brings winter to the Earth.

In Welsh mythology, a battle between two characters represents the struggle between summer and winter.

• Old Man Winter
• Jack Frost
• Ded Moroz
• Snegurochka
• Vetr