Here in Connecticut and Westchester County, New York, July has been one of the hotest Julys of all time. This has been very tough on the crews and it is also tough on a wood product, especially the horizontal surface. As the top of the surface bakes in the sun, the underside remains in the shade. This creates an obvious contrast. The closer the deck is to the ground, the more impact this contrast will have. With a dry top and cooler underside, cupping, worping and checking are the predominant results.
On these high heat days, we ask or remind our crews to drink water, often. We all know how important this practice is. We also ask them to water our deck that we are installing or just installed. We recommend to our homeowners to move the lawn sprinkler up onto the deck and saturate it. This was a practice we did many years ago with Pressure Treated Southern Yellow Pine, before all the specialized treatment systems became popular. We find this helps all the natural deck floor products with which we work, such as Ipe, Garapa, Mahogany, Cedars. And it is easy to do with no risk, as long as you close the doors and windows :-).
Most wood products like some openning up time after installation, prior to a staining or treatment such as Cabots, TWP, Sikkens, Messmer’s or one of the many others. So how do we give our new decks, built in high temperatures, the best start in their long outdoor life, prior to other methods of production? It is simple, water your crews and water your decks. Better installations, better decks. 
Custom Decks of Fairfield County Connecticut & Westchester County New York 