Answer
Land and sea breezes are caused by differences in air temperature. During the day, the land heats up faster than the sea, causing a warm air mass to rise over the land and a cooler air mass to move in from the sea, creating a sea breeze. At night, the opposite occurs, with the land cooling faster than the sea, causing a cool air mass to move in from the land and a warm air mass to rise over the sea, creating a land breeze.