The moisture holding capacity of air varies with temperature
The moisture holding capacity of air depends on the air's temperature. As you can see this diagram the capacity increase dramatically with increasing temperature.
Air Moisture Holding Capacity - SI Units
Air moisture holding capacity - kg water per kg dry air:
Air Moisture Holding Capacity - Imperial Units
Air moisture holding capacity - lb water per lb dry air:
Air moisture holding capacity - lb water per 1000 cubic feet dry air:
Note that at 100oF (38 oC) the capacity is 10 times the capacity at 30oF (~ 0 oC) . This is a very important observation, especially working with dryers where air is common for the transport of moisture away from the product.
In general it is good energy economy to increase the temperature in the dryer as much as possible since the increased moisture transport capacity of the air at higher temperatures out weights the increased energy consumption for heating the dry air to a higher temperature.