If you ask a meteorologist when winter starts, he will give a different answer than an astronomer. It just depends on whether you’re talking about climatological or astronomical winter. They both last about three months, but have a different starting point.
The difference between meteorological winter and astronomical winter
Let’s start with climate winter, because it’s coming first. Each season has a meteorological start date, which is stipulated in an international agreement. According to this calendar, spring begins on March 1, summer on June 1, and autumn on September 1.
The weather winter begins on December 1st. But according to astronomers, autumn will last a few weeks longer. Astronomical seasons take into account the Earth’s position relative to the Sun. Astronomical winter begins when the Sun is directly above the Tropic of Capricorn.
When does astronomical winter begin in 2023?
Because the solar year (the time it takes the Earth to orbit the sun) is slightly longer than the calendar year, the date on which atmospheric winter begins varies from time to time. Winter usually begins on December 21, but it also happens that the last season of the year falls on the 20thH Or 22H He makes his entrance. This is the case in 2023, when astronomical winter begins on December 22. This is also the shortest day of the year. Then we get a little extra sunlight every day.
To prevent the winter from shifting slightly each year and eventually celebrating Christmas in the summer, the leap year was introduced. Every four years we get one extra day to make up the difference between the solar year and the calendar year.
