dog days

/D AO1 G D EY1 Z/
noun
  1. 1

    The days following the heliacal rising of Sirius, now in early August (Gregorian) at dates varying by latitude.

  2. 2

    The unpleasantly hot days of late summer.

  3. 3

    Any similar period of inactivity, laziness, or stagnation.

Source: https://en.wiktionary.org/wiki/dog%20days