What country has the greatest temperature difference between its northern and southern borders?

China has the maximum temperature difference between its northern and southern borders.

Explanation:

The temperature difference ranges to almost 86 F. The temperature of China is affected by polar and Pacific air masses which bring extreme cold weather to the north.

In the south, ocean air masses bring moist weather. In the north, the dry air masses lead to cold weather whereas in the south, the temperature remains stable almost all the year round with rainfall.