How loud can a clap of thunder be, measured in decibels?

Sound velocity is proportional to the square root of temperature. Temperature typically decreases with height, unless there is an inversion (warm air over cooler air). Thus, the sound of thunder will be deflected upward. Humidity, wind velocity, wind shear, temperature inversions, terrain features, and clouds, also influence thunder's audibility.

The loudness of thunder can be expressed in decibels (dB). A clap of thunder typically registers at about 120 dB in close proximity to the ground stroke. This is 10 times louder than a garbage truck or pneumatic jackhammer drill. By comparison, sitting in front of speakers at a rock concert can expose you to a continuous 120+ dB level. Thunder in close proximity is capable of producing temporary deafness and may cause rupturing of the ear's tympanic membrane that can lead to hearing damage or deafness.