Dr. Mercola (Mercola.com, Health Articles) has stated “Humidity, or the amount of water in the air is an important health variable that is easy to overlook – yet very easy to remedy. Ideal humidity is generally described as between 40 percent and 60 percent.” Phoenix and Tucson average around 14%, while Yuma, known as the least humid city in the US, comes in with a measly average of 3 inches of precipitation per year.