No great performances when it is too hot or too cold
If the temperature goes above 25 degrees centigrade while you're playing, your head will begin to feel fuzzy. The sound is too loud even when playing lightly, and it echoes loudly inside your head.
When it is cold, the air feels heavy, and it becomes difficult to produce a sound. Furthermore, when the temperature reaches zero degrees centigrade, your sense of hearing is reduced, and it feels as if the instrument is not making a sound. Vibration is not transmitted to your body, and your fingers become numb. Thus, it is said that the ideal temperature in a concert hall is around 14.5 degrees centigrade.