From The Thaiger

Today, the National Astronomical Research Institute of Thailand announced that the Summer Solstice or ‘Srisamayan’ will result in the longest day and shortest night of the year. The sun will pause at the highest point in the north today.

The term ‘Solstice’ comes from the Indo-European word stice, meaning steady or pause. The Summer Solstice signifies the day when the sun’s path reaches its northernmost point and remains stationary. The sun’s position changes about one degree per day, and from March, it gradually moves northwards until it reaches its highest point today. After this, it will slowly move southwards.

This phenomenon results in the sun rising from the eastern horizon and leaning towards the north, and setting at the western horizon, leaning towards the north. The southern hemisphere subsequently enters the winter season, while the northern hemisphere enters summer.

The Earth’s axial tilt of 23.5 degrees, perpendicular to its orbital plane around the sun, makes various areas around the globe receive different amounts of sunlight, resulting in varying temperatures and day and night durations. This creates distinct seasons on our planet. As we can observe during summer, the days are longer than nights, indicating the sun rises early and sets later. On the contrary, during winter, the nights are longer than days, the sun rises late and sets early.

 

for Thais there's not much difference to notice between longest and shortest day but people in Northern and Southern  hemispheres know difference very well. I always cherish that moment in spring when I arrive from work and alight from the bus not in the dark for the first time.    

The summer and winter solstices have played a major part in Chinese society for millennia. Prior to the advent of the Q'ing Dynasty, the summer solstice was always marked by a public holiday and many celebrations. In Hong Kong it remains a Festival Day and the annual Dragon Boat races take place on this day.

Many buildings including Beijing's Temple of Heaven were built to celebrate the winter solstice which is virtually the second most important Festival after Chinese New Year.

In Hong Kong all businesses close at lunchtime to give employees time to get home to prepare the traditional winter solstice meal.

As one who is a lapsed Christian, I always think this is a more important reason for celebration than December 25!