What does the potentially hottest time of year have to do with dogs?
On July 23, the so-called dog days begin, which last until August 23 and typically include the hottest time of the year in our latitudes. However, the name has nothing to do with dogs, whose tongues tend to hang out of their throats when they are panting.
The origin of the naming goes back thousands of years. Because in ancient times, the rising of the constellation Canis Major (lat. Canis Major) and thus also that of its brightest star Sirius at dawn fell within this time window. In the meantime, this astronomical event has been postponed by about 5 weeks due to the proper motion of the constellation and the wobbling of the earth’s axis, known as precession. However, the name has remained and so, for example, the summer holidays in Russia are still called Kanikuly in reference to the big dog.
For the ancient Greeks, the interaction of the Sun and Sirius caused the great summer heat and Arab astronomers even recognized the dripping saliva of the great Dog Star in the heat haze.
Annual course of sun position and temperature
In fact, of course, the course of the stars has nothing to do with the course of the seasons in the Earth’s atmosphere. Rather, the time lag between the sun’s highest sand on June 21 and the greatest heat in July and August is due to the sluggishness of the oceans, which first warm up slowly over the summer and then in turn release this heat to the lower layers of the air. For this reason, it can still be summery warm well into September, while late winter can last until early April due to the slowly cooling seas.