When does spring start? Understand why the date changes every year

Just get close to the start of a new season and we see searches for “when does it start” grow in. Is summer the 20th or 21st of December? Is autumn March 21st or 22nd? No need to fight with your friend: the right answer to this question changes every year. THE springin 2019starts on the day September 23th, Monday. But this is not always the case: in 2018, for example, it was on the 22nd of September.

If you want to be 100% accurate, you can say that the most flowery season of the year will start at 23rd at 4:50 am🇧🇷 This is the day and time of spring equinox – instant when the Sun crosses the Celestial Equator. There is no mysticism in it, just astronomy. On this date, day and night are exactly the same length: 12 hours each. After that day, in the southern hemisphere, the days become longer than the nights.

Why does the beginning of spring change each year?

This happens because the interval between one spring and another – that is, the period of a year – does not have exactly 365 days. Each year has approximately 365 days and 6 hours, which makes the exact time of the equinox vary over an 18-hour period, part on the 22nd, part on the 23rd, generally.

To know the exact date and time of the beginning of spring, we can consult reliable websites such as the National Institute for Space Research or the Department of Astronomy of the Institute of Astronomy, Geophysics and Atmospheric Sciences of the University of São Paulo.