dog days 
plural noun chiefly literary
1The hottest period of the year (reckoned in antiquity from the heliacal rising of Sirius, the Dog Star).These things love the heat, and boy do they take off in the dog days of July / August....
- This is arguably the most humane and sensible solution since it saves the players from two weeks of practice under the sweltering sun and heat during the dog days of summer in late July.
- It is August, the dog days of summer, the time of squeezing hands during beach barbecues and back-to-school sales.
1.1A period of inactivity or decline: these are indeed dog days for British film production...
- Fortunately, even in the slow dog days of summer, quality rock music is an unstoppable force.
- It comes to mind now because the 2001 season is about to enter the dog days, and while we don't know yet who the winners will be come October, we can identify the losers.
- We knew that because we played our medium to small sized stadium gigs during the dog days of the third Thatcher term.