Today, you’re going to be seeing a lot of posts about how today is the Winter Solstice, the “start of winter”, the “shortest day of the year”. Both of the latter two statements are true in reality, but your perception will tell you otherwise.
Let’s start with the “shortest day of the year”. It is true that, on the solstice, there is the shortest amount of time between sunrise and sunset. But for most of us, the day doesn’t seem any shorter. Why is this? It is due to the tilt of the earth. There was a fascinating piece on the Miami PBS station related to this. During the year, due to the tilt of the earth, the sun moves from rising at true east and setting at true west. It is at its northernmost position on the winter solstice, and its summermost position on the summer solstice (I could have this backwards). This affects the length of the day. However, as we approach this position, the sunrise and sunset times don’t contract equally… and we perceive the length of the day by when it gets dark in the evening. Most of us get up after the sun has risen, so if the sunset time isn’t moving in, we don’t think the day is any shorter. The days with the earliest sunset are actually in early December. However, if you’re an early riser like me, you are affected more by the sunrise time, and that doesn’t reach its latest point until early January… when the days are actually getting longer. So our perception of the shortest and longest days is based on sunrise and sunset, not the actual length of the day.
Similarly, the “start of winter” is usually not the coldest day, just as the “start of summer” is not the hottest day. Usually those days appear to occur about half-way to two-thirds-of-the-way between the solstice and the equinox.
If you want some more details on the scientific basis behind this, see this article.
Yet another reminder that the perception of the situation is often more important than the reality of the situation.
