Great Pyrenees are not really built for the hot weather and during the hot weather they need to be kept in the shade as much as possible or bring the Great Pyrenees dog indoors where the air conditioning is to avoid the dog overheating.
Great Pyrenees can live where it's hot out but the Great Pyrenees does much better in the cold weather and snow than it does in hot weather.
Great Pyrenees love to hike with people as well in cold and snowy weather.