Why do pianos go out of tune?

Several factors cause a piano to go out of tune, and the most significant are changes in humidity and temperature. Since many parts of a piano—especially the soundboard and pinblock—are made of wood, they naturally expand and contract with fluctuations in the environment. This movement affects string tension and tuning stability.

In winter, when the air is dry, your piano will tend to go flat. In the more humid summer months, it often drifts sharp. Even if your piano isn’t played often, these seasonal shifts still impact the instrument’s pitch and overall health. And yes, normal playing also gradually pulls the piano out of tune over time.

You might ask, “But I barely play my piano—do I still need to have it tuned?”
The answer is a resounding yes. Piano strings are under tremendous tension—often over 30,000 pounds combined—and without regular tuning, that tension can become uneven. Over time, this may cause your piano's pitch to drop significantly and could even lead to string breakage or other costly repairs.

Think of piano tuning like changing the oil in your car: it’s essential maintenance. You wouldn’t wait until your engine starts grinding to schedule an oil change—so don’t wait until your piano is drastically out of tune to give it the care it needs. Regular tunings help preserve your instrument’s tone, stability, and longevity.