When parking your car, it's better to park in the shade than in the sun. The temperature inside the car will be different.
You should park your car in the shade than in the sun. The inside of the car won't be as hot.
「車を駐車する時は、日なたよりもなるべく日陰の方がいいよ。車内温度が違うから。」というのは、このように言えます：
When parking your car, it's better to park in the shade than in the sun. The temperature inside the car will be different.
park a car = 駐車する
it's better to = ～した方がいい
in the shade = 日陰
in the sun = 日なた
temperature = 温度
(be) different = 違う
また、もう１つ省略して、言い回した文も紹介します：
You should park your car in the shade than in the sun. The inside of the car won't be as hot.
you should ～ = するべき・した方がいい
The inside of the car won't be as hot. = 車の中は比較的に暑くなりません。
アメリカ合衆国 
