Why Coastal Areas Are Hotter

Humidity is defined as water in the form of vapor that saturates the ambient air . This vapor originates from the evaporation of water that takes place in water masses (rivers, lakes, oceans, etc.) or that which comes from living beings.

Given its greater proximity to the sea, coastal areas have higher humidity than those areas that are inland. This influences the thermal sensation, but not the temperature as such, for example in feeling more heat in the coastal areas and a more penetrating cold in the interior.

The reason is that the human body loses heat by releasing high-temperature sweat, which evaporates to extract heat. When there is more water vapor in the environment, the ability of the water in our sweat to evaporate decreases and the sweat does not perform the function of extracting heat. For this reason, with humidity and although we also sweat, our body loses part of the ability to cool down and our thermal sensation is greater.

Altitude and heat

As a general rule, the higher the altitude, the lower the temperature. It is calculated that the temperature decreases by 0.65º C for every 100 meters of elevation. Coastal areas tend to be less elevated than inland areas (sea level is 0 altitude) and the temperature on the coast may be higher .

The reason for this is that the earth’s surface absorbs heat from solar radiation and releases it to the layer closest to the surface. Thus, the further a layer of air is from the surface, the colder it will be. The exception to this are the phenomena of thermal inversion.

In the coastal vicinity, seawater absorbs heat from radiation and releases it very slowly , while rocks also absorb heat and release it more quickly. Thus, a temperature difference is created between land areas and water areas. This factor produces local winds called sea ​​breezes . During the day, the land is warmer, so that the air above it rises and gives way to cooler air that blows from the sea, while at night the opposite process occurs, that is, the sea is warmer and the air in it rises, to give way to the cooler air that blows from the ground.

However, the marine influence is not only reduced to the creation of sea breezes, but throughout the year they serve as regulators of the local temperature. In times of higher temperatures, such as spring and summer, the sea absorbs large amounts of energy in the form of heat and, together with the higher levels of evaporation, the air temperature is lower. As a consequence, the average temperatures in the territories closest to the sea are lower than in the interior, during the hottest times.

On the contrary, in times of lower temperatures, the heat that has been absorbed by the seawater is gradually released, warming the air temperature. Furthermore, in this period, the phenomenon of evaporation and condensation of water masses causes the relative humidity in coastal areas to be higher than in the interior of the continent. The marine influence can reach several kilometers inland, due to the movement of air masses. This is why in the colder times, in the coastal areas it is not perceived as cold as in the interior.