WITH THE AIR conditioner turned off, a cleaning rag left flat to dry overnight on the sink’s edge was musty by morning. But the heavy air was thinning out and a wind was picking up as the sun, unsoftened by haze, baked down. The screen of a phone with its camera pointed skyward was overwhelmed by reflections, filled with the stripes of the camera-holder’s shirt. A notebook page was too white to read. A Dalmatian puppy hung its head and front paws out an SUV window to look around. Wind-lofted trash floated and tumbled in the sun as high up as birds. People leaving the Park were red with overheating or sunburn. For a moment, the hissing wind through the trees rose louder than the roller-disco beat.