When does an inversion occur in the atmosphere?

An inversion occurs in the atmosphere when the surface air is warmer than the air above it. This phenomenon is known as a temperature inversion and typically happens when the normal temperature gradient of the atmosphere is inverted; that is, the temperature decreases with altitude but instead starts to increase.

In this situation, warm air at the surface traps cooler air above it, creating a stable atmospheric layer. This stability can restrict vertical mixing and potentially lead to the accumulation of pollutants and poor air quality near the ground.

Nighttime cooling can enhance this effect, as surfaces cool quickly while the air just above can remain relatively warm, hence the inversion can often be more pronounced during the night, but it is not confined solely to that time. Factors like humidity may influence local weather conditions or visibility but are not direct indicators of inversion occurrence.