What time of day is relative humidity usually at a minimum?

Relative humidity is typically at a minimum during the early afternoon due to the diurnal cycle of temperature and its direct influence on water vapor capacity in the air. As the sun rises and warms the surface, the temperature increases, allowing the air to hold more moisture. With temperatures peaking during the early afternoon, the absolute amount of moisture in the air might not increase correspondingly, leading to a lower relative humidity percentage.

In contrast, during the nighttime and early morning hours, temperatures are generally cooler, often resulting in higher relative humidity as the air can hold less moisture at lower temperatures. Thus, at midnight and dawn, relative humidity tends to be higher. In the evening, as temperatures begin to drop again, humidity may also increase. Therefore, the early afternoon is identified as the time when relative humidity values usually reach their lowest point.