How hot does this grass get, say in arizona?

It depends on how hot the weather gets. Using Arizona as an example, in a hot day of 100 degree F, the turf temperature can get up to 150-170 degree F. That is why we already recommend to use TCool infills on artificial grass in extremely hot areas like Arizona. Here is the link to our TCool infill: 

https://www.globalsynturf.com/tcool

With the TCool infill, we can reduce the turf temperature by as much as 50 degrees F, you shall see a testing video on our test from the above link.