text: if a weather report indicates that the relative humidity is 90%, what would happen if the temperature dropped? if a weather report indicates that the relative humidity is 90%, what would happen if the temperature dropped by ten degrees celcious? all other factors remaining constant, the relative humidity would increase. relative humidity refers to the amount of water dissolved in the air as a percentage of the total amount of water the air, at that temperature, can hold. the warmer the air, the greater its capacity to hold water. it rarely snows in antartica because the average temperature is so low the air can only hold a very small amount of water.   summing up; it is called relative humidity because the actual amount of water in the air does not alone determine the relative humidity. it is a function of the temperature of the air, ergo its capacity to hold water,  as well.  as an aside: even at 100% relative  humidity air can only hold a maximum of 4% water by weight.