Extreme swings from hot to cold or dry to wet are harmful to your piano. Dryness causes the piano‘s pitch to go flat; moisture makes it go sharp. Repeated swings in South Florida’s relative humidity can cause soundboards to crack or distort. Extreme dryness can also weaken the glue joints that hold the soundboard and other wood portions of the piano together. Moisture may also lead to string rust. A piano functions best under fairly consistent conditions which are neither too wet nor dry, optimally at a temperature of 68 degrees F and 42 percent relative humidity. A dehumidifier left in the room where the piano is located will help the humidity and moisture under control, thus saving your soundboard for many years to come.