Winter is the coldest season of the year. The Northern Hemisphere, the northern half of Earth, has winter weather from December to early March. Winter storms produce large snowfalls in some areas, shown here. In the Southern Hemisphere, winter weather begins in late June and lasts until early September.
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Tuesday, Dec. 21, 2021 is the winter solstice for the Northern Hemisphere. On the winter solstice, the sun is at its most southerly position. It marks the day in the year with the least amount of sunlight and the beginning of winter. After the winter solstice, days begin growing longer and nights shorter approaching spring. The winter solstice in the Southern Hemisphere happens in June because the seasons are reversed. December 21 in the Southern Hemisphere is the summer solstice, the longest day of the year.

During the winter solstice, the sun is directly overhead at the Tropic of Capricorn. The Tropic of Capricorn is an imaginary line that traces the southern boundary of the earth’s Tropical Zone. It marks the farthest limit south of the equator where the sun can appear directly overhead. The change results from the tilt of Earth’s axis of rotation. The winter solstice in the Northern Hemisphere happens on December 21 or 22.

Earth spins around its axis once every 24 hours. This motion creates day and night. Earth also travels around the sun once every 365 days. This motion creates the year. The entire solar system revolves around the center of the Milky Way Galaxy.

On the winter solstice which occurs in December in the Northern Hemisphere and June in the Southern Hemisphere, people celebrate the rebirth of the sun and the beginning of winter. For a long time, cultures around the world have celebrated holidays and feasted around the winter solstice. Most of the celebrations feature light since it occurs on the darkest day of the year.

Stonehenge may have been a place where people celebrated the winter solstice. Stonehenge is an ancient ruin in southwestern England. It consists of huge, rough-cut stones set in a circle. The stones are aligned toward the winter solstice sunset. There is archeological evidence the people who lived there held a large feast on the winter solstice.

Ancient Roman holidays were planned around the winter solstice. People have also celebrated specific holidays on the winter solstice in China, Iran, Japan, and Scandinavia. The Incas and some Native American tribes celebrated the winter solstice by fasting, dancing, and then feasting.

December 9, 2019

If your birthday is in December, you have the choice of three bluish birthstones—the gems associated with the month of your birth—turquoise, zircon, and tanzanite. Turquoise is a mineral widely used as a gemstone. It is prized for its color, which ranges from sky-blue to blue-green or yellow-green. The mineral zircon comes in many colors, but the blue variety is most popularly worn in jewelry. Tanzanite, a semiprecious gemstone, is a type of a mineral called zoisite. Trichroic (three-colored) tanzanite crystals are often deep blue or purple.

Turquoise is a bright blue or blue-green mineral widely used as a gemstone. Credit: © Akulinina Olga, Shutterstock

Turquoise is relatively soft, and so it is easy to shape and polish. It has a dull, waxy luster and is nearly opaque (nontransparent). Turquoise consists chiefly of a hydrous aluminum phosphate, a compound in which aluminum and phosphorus are chemically combined with water. It also contains copper, which gives it its bluish color. Turquoise occurs in the arid regions of Iran, Tibet, Mexico, and the southwestern United States. The mineral’s pastel blue color made it popular with royalty and others of importance from these areas, particularly in the ancient Chinese, Egyptian, Persian, and the Aztec and other Native American civilizations. Turquoise was once thought to promote good health, wealth, and protection from evil spirits.

Zircon is a birthstone of December. Credit: © Shutterstock

Zircon originates in the ancient layers of the Earth’s crust. It is composed chiefly of the elements silicon, oxygen, and zirconium. Zircon also contains smaller amounts of such elements as hafnium, iron, and the lanthanides. Some zircons also contain the radioactive elements thorium and uranium. Zircon crystals may be reddish-brown, yellow, green, blue, or colorless. The colorless variety of zircon can sometimes resemble a diamond, but it is not to be confused with the unrelated synthetic diamond substitute, cubic zirconia. Zircon is used in the ceramics industry and in making parts for nuclear reactors. Blue zircon crystals have long been used for jewelry. In ancient times, the mineral was thought to have calming properties that aided sleep, decision-making, self-confidence, and general wisdom. Zircon is found in many parts of the world, but Australia produces more of the mineral than any other country.

Tanzanite is a relative newcomer to both the birthstone list and the world at large. The mineral was discovered in 1967 in Tanzania, for which it was named, and added as a December birthstone in 2002. Tanzania is the only known source of tanzanite. Because the supply is limited, it is quite expensive. Tanzanite is cut into gemstones with numerous facets (flat, polished surfaces), which emphasize its light-reflecting quality. The gemstones are used in such jewelry as rings, earrings, and pendants.

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Birthstones, according to tradition, bring good luck when worn by a person born in the associated month. Credit: WORLD BOOK illustrations by Paul D. Turnbaugh

According to tradition, a birthstone brings good luck to a person born in its month. Each birthstone also corresponds to a sign of the zodiac. The belief in birthstones may have come from a Bible story about Aaron, the first high priest of the Israelites. The story describes Aaron’s breastplate, which was decorated with 12 precious stones. Early writers linked these stones with the 12 months of the year and the 12 signs of the zodiac. The custom of wearing a stone that represented a person’s zodiac sign probably originated in Germany or Poland in the 1700′s.

December 29, 2015

Today, Tuesday, December 29, 2015, marks the fourth day in the 49^th annual observation of Kwanzaa, a uniquely African American celebration. The celebration begins on December 26 and lasts for seven days. This year, millions of people in the United States will take part in Kwanzaa festivities and observe the seven principles upon which it is founded. As the fourth day of Kwanzaa, today is dedicated to Ujamaa (cooperative economics), and people are asked to support local small businesses in their community.

Kwanzaa is an African American holiday that begins on December 26 and lasts for seven days. The holiday centers on seven principles. Each evening, families exchange gifts, light one of the seven candles, and discuss the day’s principle. This child is shown lighting one of the seven candles. Credit: © Corbis

Kwanzaa centers on the Nguzo Saba, seven principles of black culture. On each day of the holiday, one of the principles is emphasized. Each evening, families light one of the seven candles in the kinara (a candleholder) and reflect on the day’s principle. The principles of Kwanzaa are Umoja (unity), Kujichagulia (self-determination), Ujima (collective work and responsibility), Ujamaa (cooperative economics), Nia (purpose), Kuumba (creativity), and Imani (faith).

Kwanzaa festivities usually end with a joyous feast called karamu. Among families, karamu usually involves traditional African American foods, ceremonies honoring ancestors, and reflection on the old year and commitments for the new. Many cities across the United States hold public Kwanzaa observances. These often include performances, music, and dancing. The traditional colors of Kwanzaa are red, black, and green. These three colors have long represented Africa and are found on the flags of many African countries. Green represents the fertile land of Africa. Black represents the people of Africa, and red represents the blood that has been shed in the struggle for freedom for African nations.

Kwanzaa was developed in 1966 in the United States by Maulana Karenga, a black cultural leader and professor of Pan-African studies at California State University in Long Beach. The 1960’s, at the height of the civil rights movement, were a time of social upheaval and change for many African Americans. Karenga wanted to create a celebration that would honor the values of African cultures and inspire African Americans to strive for progress. Karenga based this celebration on harvest festivals common in many African societies at this time of year that had existed for thousands of years. He called the celebration Kwanzaa, sometimes spelled Kwanza, based on the phrase matunda ya kwanza, which means first fruits in Swahili (also called Kiswahili). He chose to use Swahili terms for the celebration because this language is widely used by various peoples in East Africa.

Other World Book articles: 

• Christmas
• December