1. How Temperature Affects Humidity Temperature Humidity This Graph shows the relationship of between Humidity and Temperature. This graph shows that when the temperature is the highest the Humidity is the lowest. Relative humidity decreases with a rise in temperature because; the relative humidity depends not only upon the amount of water vapor actually present but also on the air temperature. If no moisture is added, an increase in temperature will result in a corresponding decrease in the relative humidity. For example, since warm air has a greater capacity for water vapor, desert climates with dry air can have single-digit relative humidity’s since the air is very far away from reaching saturation.