6 facts about the winter solstice

1. The magic moment

While many focus on the winter solstice as a day in the calendar, what we are actually talking about is a very specific moment which is over almost as soon as it has begun.

The solstice marks the point at which the Sun is exactly overhead the Tropic of Capricorn, which this year will happen on Friday, 22 December at 03:27 GMT.

2. The Sun stands still

Like many other astronomical terms, the word solstice comes from Latin. Owing to the Sun appearing to 'standstill' in the sky when it reaches the Tropic of Capricorn, the word solstitium was used which in turn is composed of the words sol (meaning 'sun') and sistere (meaning to 'standstill').

3. Winter begins

As well as marking the shortest day of the year, the winter solstice marks the first day of winter in the astronomical calendar, whilst in the meteorological calendar, we are already three weeks into winter.

4. Nine hours darker

You're probably aware that the day of the winter solstice marks the shortest day of the year, but did you know that its almost nine hours shorter than the longest day of the year?

The summer solstice in June is just short of 16 hours and 38 minutes long, while on the day of the winter solstice the length of the day is a mere 7 hours and 50 minutes.

5. The earliest sunset

Logically you'd expect the earliest sunset to fall on the shortest day, but the earliest sunset actually occurs a few days earlier in the calendar and it's all to do with our clocks not quite mirroring the Earth's orbit.

True solar noon, the point at which the Sun reaches its highest point in the sky, occurs around 10 minutes earlier than when our clocks strike 1200, and it is this discrepancy that means the sunset also arrives a little later on the solstice.

6. Solstice and Christmas

Amongst the many festivals that centre around the solstices and equinoxes, the Scandinavian festival of Jul has some rituals that are probably more familiar than you think.

Perhaps more familiar to us as Yule, the 12-day festival centred around the solstice has given birth to many of our most familiar Christmas traditions including the Christmas tree, the Yule log and the Christmas wreath.