Monday, the 22nd of December. This is the first day of winter, according to the Spanish National Astronomical Observatory. The season will last 88 days and 23 hours, finishing on the 20th of March with the beginning of spring.
What we call a year is a complete circuit of the Earth around the Sun. On this 365-day journey, there are times when the Sun rises high above us, and others when the Sun stays close to the horizon. When the arc traced by the Sun in the sky is long, we are in summer, and when it is short there is less light and heat, and we are in winter.
Today that arc will be shorter than on any other day. However, there is cause for celebration, because although this is the day when the Sun rises later and sets earlier than at any other time, this is also the moment from which the days begin to get longer, by about 1 minute per day.
May the light be with you!
Happy winter solstice.—