Dressing for the Gulf Summer

A dog does not sweat the way you do. It sheds heat almost entirely by panting, which means the hotter and more humid the air it is breathing, the less that mechanism works. In a Gulf summer, the air stops helping.
The ground is hotter than the air
Paving, asphalt and sand hold radiant heat long after the sun has moved, and they sit well above whatever your phone says the temperature is. Press the back of your hand flat to the ground and hold it there. If you cannot keep it there for seven seconds, it is too hot for a paw pad.
Move the walk, not the dog
Between May and September the walk belongs at first light and after dusk. Not midday, not because the schedule is inconvenient. Shade, water and a shorter route beat a long walk at the wrong hour every time.
Some dogs have less margin than others
Flat faced breeds have a shortened airway and far less cooling capacity. A French Bulldog, a Pug or a Shih Tzu will reach distress in conditions a longer muzzled dog tolerates easily. Watch for laboured or noisy panting, a bright red tongue, unsteadiness, or a dog that simply sits down and will not move. Cool them with tepid water, never ice, and call a vet.
What a coat is for in summer
It sounds like a contradiction, and it is not. A light, breathable layer protects a thin or pale coat from direct sun, and it keeps a short haired dog off cold surfaces in the aggressive air conditioning that defines an indoor Gulf summer. What you avoid is anything heavy, anything dark, and anything that traps air against the skin.