Why is it colder on clear nights without wind?

Arabia Weather - On calm nights characterized by the absence of clouds and calm winds, the atmosphere takes on a charming character and remarkable calm. In this context, the weather is considered colder during clear nights without the presence of wind.

Why is it colder on clear nights without wind?

This phenomenon, familiar to astronomy enthusiasts, occurs regularly throughout the year. Whereas on clear nights, this is often accompanied by a drop in temperatures in the evening and during the day when there are clouds, the environment is generally cooler compared to clear nights, as clouds trap more heat in the atmosphere.

The influence of the sun's rays decreases until infrared rays stop arriving, and in the case of a cloudy sky, radiation and heat cannot penetrate, as they are trapped by clouds. In contrast, when there are no clouds, this heat and radiation are discharged, and since there is no barrier to store them, we are left with a cold night and thus, a clear, starry sky.

Similarly, during the day, the formation of clouds prevents radiation from penetrating the ground level. When bright solar rays collide with clouds, refraction occurs, where the direction of the ray changes because it passes through a different medium than the one it came from. The term is called “reflected” if the ray bounces and changes direction. upon collision.

For example, this effect is clearly observed in summer on very hot and sunny days, when cloudy nights limit the dissipation of stored heat, leading to hot and unpleasant nights. The effect of clouds is reflected on thermometers at specific times during the day, and clouds are cool during the day and retain heat. While it is warm at night, and when it is absent during the day, the temperature drops at night. This is why deserts have high daytime temperatures and cold nights, when the sky is almost clear, which contributes to the formation of a noticeable thermal contrast.

The effect of wind also comes to the fore, as winds can contribute to slowing down the cooling process at night, and if the winds are calm, temperatures may drop faster. Wind direction also plays a role, as southern winds make the atmosphere warmer, while northern winds may increase Cooler weather, and in the event of calm winds, temperatures are expected to drop more quickly during the evening and night.

Also know:

Why is the sun cold in winter?

7 easy steps to becoming a winter morning person

Sources:

meteorologiaenred