In a figurative sense: a period of stagnation

Yet another loss by our soccer team. This proves that these are really dog days for our city team

La nostra squadra di calcio ha perso ancora una volta. È la conferma che la squadra cittadina sta attraversando giorni duri

The ancient Romans linked the apex of summer heat to the influence of Sirius, which is the brightest star in the sky. It is located in the constellation of Canis Major, meaning the "Big Dog", that's why Sirius is also known as the "Dog Star". The Romans called these days Dies Caniculares, which was translated as Dog Days in the 16th century