What Is Winter?

Winter is one of the seasons, occurring between autumn and spring. It is the coldest season, with temperatures dropping and the days getting shorter. Some animals hibernate during this time, and in temperate climates there is often snow. People wear warm clothing and enjoy winter sports such as skiing, snowboarding, and ice skating. Many countries have winter holidays such as Christmas and New Year's Day.

Winter begins with the shortest day of the year, which is known as the winter solstice. It is when the sun's rays reach the Earth at their most indirect angle, giving less warmth and causing snow to form.

The shortest day of the year occurs around December 21 or 22 in the Northern Hemisphere and June 21 or 22 in the Southern Hemisphere. It is also when the nights are the longest and the sun's rays reach the least of the Earth's surface.

After the winter solstice, the Sun begins to rise higher in the sky again, gradually lengthening the days and warming the planet. However, this increase is far from uniform. For example, the North Pole experiences much warmer weather than the South Pole. The reason is that the axis of the Earth's rotation rotates between the hemispheres, and each hemisphere is tilted away from or toward the Sun at different times during the year.

Animals adapt to the chilly temperatures of winter by growing thicker fur or feathers for insulation, or migrating to warmer regions. Some animals, such as bears, hibernate during the winter, which means they enter a deep sleep to conserve energy. Others, such as birds, migrate, flying thousands of miles to find warmer places where they can find food and lay eggs.

During the winter, some plants die and leave their seeds, and others become dormant until the resumption of growth in spring. This dormancy is known as a "winter break." In the United States, winter has recently been warm. For a large swath of the country from Colorado to New Jersey, and from Texas to the Carolinas, it has been more like a spring or summer. This is because long-term warming has caused the Arctic to warm three to four times faster than the rest of the world, shifting the weather patterns of the whole nation.

Nevertheless, the period of lowest average temperatures typically lasts from late November or early December through late February or early March. It is during this time that the astronomical winter officially begins, though meteorologists (people who study weather and climate) define when it starts based on temperature records. This definition of winter is also called the "thermological winter." The first official day of the winter season is sometimes referred to as the first day of Winter. Winter may not be over, however, as some experts predict that it will continue to get warmer. Ultimately, this might mean that winter will change in ways that we cannot fully understand now. It will be interesting to see how this unfolds.