I was curious as to what the "dog days of summer" meant, so I looked on Wikipedia...
The dog days or dog days of summer are the hot, sultry days of summer. They were historically the period following the heliacal rising of the star system Sirius (known colloquially as the "Dog Star"), which Hellenistic astrology connected with heat, drought, sudden thunderstorms, lethargy, fever, mad dogs, and bad luck. They are now taken to be the hottest, most uncomfortable part of summer in the Northern Hemisphere.
"Okay, I'm gonna put you in charge. You take care of the car. You're a responsible dog. When I get back, if the car's okay, I'll give you a cookie. If the car's gone....I'll give you another cookie anyway. Cause I love ya."