Explain why:
Coastal areas maybe affected by land and sea breezes because they are located in between the land and the sea. Differences in heating of the land and sea causes pressure differences. As such with pressure differences, wind is created and temperatures around the coastal areas is affected especially during the day and night.

Explain how:
During the day, the land heats up faster than the sea. An area of low pressure is created over the land while an area of high pressure is created over the sea. Air moves from high pressure to low pressure. As such, cool air from the sea moves inland towards the coastal areas which is known as sea breezes that lowers coastal temperatures during the day.

Whereas during the night, the land cools faster than the sea. An area of high pressure will be created over the land while an area of low pressure is created over the sea, With air moving from high to low pressure, air from the land will move towards the sea. As such, land breezes is generated which warms the coastal areas during the night when the air moves from the land towards the sea.