Winter

Winter is the coldest and darkest season of the year in temperate and polar climates. It comes after autumn and before spring. During winter, the part of Earth where you live turns away from the Sun. This happens because Earth's axis is tilted.

When it is winter in the Northern Hemisphere, it is summer in the Southern Hemisphere. The opposite is also true. Winter often brings precipitation. This can be rain or snow, depending on where you live. The winter solstice is a special day. On this day, the Sun is at its lowest point in the sky. We have the shortest day and longest night of the year. After the solstice, the days slowly get longer and the nights shorter.

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

Etymology

The English word winter comes from an old language called Proto-Germanic. It sounds like wintru-. We do not know where this word came from. 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 gives us the seasons. When one part of the Earth faces away from the Sun, it is winter there. The other part faces the Sun and has warmer weather.

In winter, the Sun is lower in the sky. Its light hits the Earth at an angle. This means less warmth reaches the ground. The light also passes through more air, which cools it down.

Places can have very different winter temperatures even if they are close together. For example, Winnipeg in the Great Plains area of Canada can be very cold. Vancouver on the west coast stays milder because of the nearby ocean and winds.

Timing

Meteorological reckoning

Further information: Meteorological seasons

Meteorological winter is measured by meteorologists using weather patterns. 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. 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. Many change their behavior to survive the cold.

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 affected many places.

In the winter of 1683–1684, the River Thames in London froze thickly, and people could 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.

Effect on humans

Winter can make it harder for our bodies to stay warm. This can cause health problems. Slippery ice can make people fall and get hurt.

The cold can cause problems like hypothermia. This is when the body gets too cold and can’t move well. Another problem is frostbite. This is when skin freezes and can get damaged. There are also conditions like trench foot, where feet feel numb and can be harmed, and chilblains, which affect small blood vessels.

During winter, people can 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 take care of ourselves during this season.

Mythology

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

In Greek mythology, winter happens because the goddess Demeter feels sad when her daughter Persephone is away. Hades took Persephone to live with him, and she spends half the year with each of them. When Persephone is away, Demeter’s sadness brings winter to the Earth.

In Welsh mythology, a battle between two characters shows the fight between summer and winter.

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