"Dog days" refer to the hottest and most oppressive days of summer, typically occurring in the period from early July to mid-August in the Northern Hemisphere.
The term finds its origins in ancient astronomy and mythology, specifically in the heliacal rising of the star Sirius, the brightest star in the constellation Canis Major (Big Dog). In ancient Greek and Roman cultures, the appearance of Sirius on the horizon just before sunrise was thought to coincide with the hottest days of the year.

The name "dog days" stems from the association with Sirius, often referred to as the "Dog Star" due to its place in the constellation of the Big Dog. The belief was that the combined heat of Sirius and the sun during this time led to a period of extreme heat. Over time, the astronomical significance of the term has diminished, but "dog days" continues to be used to describe the sultry and oppressive weather of midsummer. The phrase has also taken on a metaphorical meaning, describing a period of stagnation or inactivity. In modern language, "dog days" conjure images of scorching temperatures and the need to seek relief from the summer heat.