Which condition generally results in lower relative humidity?

Increasing temperature generally results in lower relative humidity because warm air has a higher capacity to hold moisture compared to cooler air. As the temperature rises, the amount of water vapor that the air can hold increases, which means that if the amount of moisture in the air remains constant while the temperature rises, the relative humidity will decrease. This principle is essential in understanding weather patterns and is particularly relevant in firefighting conditions, where lower humidity can lead to a higher risk of fire as fuels can dry out and become more combustible.

In contrast, precipitation typically adds moisture to the air, thereby increasing relative humidity. Higher fuel moisture indicates that fuels contain more water, which can also help maintain humidity levels. Nighttime conditions often allow for cooler temperatures, which can lead to increased humidity as the air cools and its capacity to hold moisture lowers, potentially resulting in condensation.