The conventionally established date is one thing and the astronomical calendar is another. Students took to the streets yesterday to celebrate the arrival of spring, but in 2021 that season It starts this Wednesday, the 22nd, at 4:20 pm, when it will take place on the equinox.
Spring has a very variable climate, with sunny days but also abundant rainfall. Temperatures also experience large thermal fluctuations between day and night.
According to the astronomical calendar, the spring season starts at spring equinox; that is, when the Earth is in the center of the Sun’s orbit, which occurs between September 21 and 23 in the southern hemisphere and ends with the summer solstice – around December 21 or 22 -. The exact date varies from year to year.
At this moment both hemispheres of the Earth are at the same distance from the sun. That’s why day and night last the same.
Equinoxes and Solstices
The equinoxes and solstices are events that mark the beginning of the astronomical seasons, whose dates do not coincide year after year.
Only after a cycle of 400 years the seasons they start again on approximately the same days.