III. Weather Phenomena

8. Land-sea breezes

In addition to seasonal changes, the temperature of the surface of the sea and land also experience diurnal changes during a day. However, since the scale is smaller it will influence only the coastal areas.

In areas close to the shore, in daytime the land is warmer than the sea. Therefore the air pressure of the land is lower than the sea. As a result, wind usually blows from the sea to the land. Such type of wind is called a "sea breeze". After nightfall, the situation is reversed, wind blows from land to sea and is called a "land breeze".

Sea breezes usually begin at 10-11 a.m. At first the force and range will be small, until 2 to 3 p.m. when the temperature is highest, at which point the sea breeze is also the strongest and can often reach a scale force 3-4 on the Beaufort scale. However, it can only reach to 20-25 km inland at most.

After sunset, sea breezes will stop and land breezes will begin. A land breeze is not as obvious as a sea breeze; usually its force is only scale 1 to 2.

Land-sea breezes usually occur in low-altitude areas, usually not over 200-300 meters, the maximum being 600 meters.

A sea breeze is obvious in tropical regions, but in the mid-latitude regions due to other factors it is not obvious. The region with the strongest sea breeze is the Guinea Bay in Africa. Every day after 2 p.m., when the weather is at its sultriest there will often be refreshing cool breezes coming from the sea. That's why the locals call this wind "the doctor" for its ability to cure the sultry weather. An Englishman, who lives in cold and wet regions, may be terrified by a hot weather. The only reason he might be able to stay for a long period of time in Singapore is due to the fact that the seashores are graced by strong sea breezes.