For a given mass of air, how does temperature affect relative humidity?

Question

Organisms lose water faster in atmosphere with low or high relative humidity?

Answer 1

When temperature increases, the relative humidity decreases.  Dew points measure relative humidity, so if the dew point and the air temperature are the exact same, then the relative humidity is 100%.   The farther the temp is away from the dew point, the lower the humidity.  In the summer time if the air temperature is 90, and the dew point is 30, you have extrememly low humidity and if the dew point is 70, you have moderately high humidity.  And as far as the organisms go, i would imagine if they lose water faster with low relative humidity because you don't have any moisture.

Answer 2

The cooler the air dryer it is most likely to be (especially if it is continental/polar) and the warmer (especially if it is maritime) the air the more moist it will be. Warm air can hold more moisture than cooler air.