Below are pictures of Polish Lowland Sheepdog puppies or PON puppies as they are often called.  Polish Lowland Sheepdog  puppies  original name was Polski Owczarek Nizinny, but in going into AKC the name was simplified.    As you will see PON puppies come in all colors, however, they may vary throughout their lives.  Some go lighter, and even eventually turn darker again as they age.  Because of this color change, it is wise of your breeder to  advise against buying a puppy just because you like its color. 
I have just completed a 15 hour journey to my new home from the Netherlands.   I don't think I look too bad for wear all things considered. And now for a quiet nap...I have to get past this jet lag thing......They say I have a future "boyfriend to meet!
This picture is not meant to be a cute pic but a strong reminder that summer and PONs  (or any dog of puppy for that matter) present a dangerous situation for your beloved family member.  Cars can heat up in less than 5 minutes even with the windows open and the car parked in the shade.   If you leave the windows more open the dog may escape or be stolen!   Bottom line in the hot days of summer leave your dog home where he is safe!
If you must take him along on a trip, find places to eat where you can park in the shade , keep him crated,  and open all windows and tailgates if possible. Either eat in the car with him or park where you can see the car at all times, and do not forget to keep an eye on him at all times.   Sometimes I have found that some nicer restaurants will even find a place where you can put him if he is crated...so do ask.  The main thing is to watch and make sure he remains safe.