Explain why summer in the Northern Hemisphere is cooler than summer in the Southern Hemisphere.

Because of the earths tilt the northern hemisphere does not receive as much direct sun as the lower part of the earth. There for it is cooler.

Land warms more quickly than water due to the very high specific heat of water. Because the Northern hemisphere has more land than the Southern Hemisphere, it is warmer in the summer even at the same amount of temperature.