Comprehensive resource for understanding and mastering English idioms
The "dog days of summer" is an idiom that refers to the hottest and most humid time of the year, typically occurring in July or August in the Northern Hemisphere. The term comes from the ancient belief that Sirius, the brightest star in the constellation Canis Major (the Greater Dog), appeared to rise just before sunrise during these months.
The term "dog days" dates back to ancient times, when people believed that the star Sirius was responsible for the hot and humid weather. The idiom has been used in English since at least the 16th century, with early recorded uses appearing in poetry and literature. Over time, the term has come to refer specifically to the hottest time of the year, regardless of the constellations that are visible in the sky.