Here's how it works:
* During the day: The land heats up faster than the water. The warmer air over the land expands and becomes less dense, causing it to rise. Cooler, denser air from over the water moves in to replace the rising air, creating a sea breeze blowing from the sea towards the land.
* During the night: The land cools down faster than the water. The warmer air over the water expands and becomes less dense, causing it to rise. Cooler, denser air from over the land moves in to replace the rising air, creating a land breeze blowing from the land towards the sea.
So, the sea and land breezes are essentially the same phenomenon, happening at different times of the day due to the different heating and cooling rates of land and water.
