What is the relationship between temperature and relative humidity?

The relationship between temperature and relative humidity is characterized by an inverse relationship. When the temperature increases, the air's capacity to hold moisture also increases, meaning that the relative humidity, which is a measure of the current amount of moisture in the air relative to the maximum it can hold at that temperature, will decrease if the moisture content remains constant. Conversely, if the temperature decreases while the moisture content remains the same, relative humidity will increase.

In essence, as the temperature rises, the same amount of moisture in the air becomes a smaller fraction of the total moisture that the air can potentially hold, leading to lower relative humidity. This dynamic is crucial in understanding fire behavior, as lower relative humidity can contribute to drier conditions that can enhance fire intensity and spread.