Santa and a reindeer by the tree under the moon

About this drawing

Santa at night under a glowing moon is a reminder that December brings the longest nights of the year in the Northern Hemisphere. Christmas falls just a few days after a special moment in the sky: the winter solstice.

The winter solstice happens around December 21 or 22. On that day the sun rises late, stays low in the sky and sets early, giving us the shortest day and the longest night of the year. It happens because Earth's axis is tilted, so in late December the Northern Hemisphere is angled away from the sun.

From then on, the days grow a little longer. For thousands of years, people have marked this turning point with festivals of light, bonfires and candles to welcome the sun's return. Some of today's holiday traditions, like twinkling lights, echo that ancient idea.

South of the equator, it is the opposite: December is summer, and Christmas arrives with the longest days of the year. In places like Australia, families often celebrate with barbecues, beach trips and backyard picnics, and Santa sometimes swaps his heavy coat for something cooler.

• santa
• reindeer
• christmas tree
• night
• winter solstice