We live in NC which is a little cooler, but I have seen my basenjis laying in the sun when it is 100F or when it is 40F. We can't leave them in the house all day due to destruction, but a laundry room they can go into with a dog door as well as a seperate room in the garage with a dog door. Plus we have a table with umbrealla on teh deck and they will move between full sun and any of those areas when they feel like it.
Even when we are home all day they alternate between inside and outside in teh sun.
I have the same setup. I keep Buddy, 8 months old outside with the dog door blocked as he would be destructive inside while the weather is mild. Come winter I will have to just let him have access to the laundry room only as that's where the dog door enters and keep the laundry room door to the rest of the house closed. There's also a door going into the garage.