Across thousands of reported sightings spanning several centuries, ball lightning displays a remarkably consistent set of characteristics. The phenomenon typically appears as a luminous sphere ranging from the size of a golf ball to a basketball, though rare reports describe much larger instances. Colors vary but are most commonly described as white, yellow, orange, or blue-white.
The sphere usually appears during or immediately after a thunderstorm, often in proximity to a conventional lightning strike. Ball lightning moves through the air at walking speed or slower, sometimes hovering in place, and can pass through solid objects including walls, windows, and aircraft fuselages — a characteristic that challenges most physical models. Duration ranges from a few seconds to rarely several minutes. Disappearance is either gradual (the sphere dims and fades) or sudden and explosive (with a loud bang and sometimes physical damage to nearby objects).
Some witnesses report a sulfurous or ozonic smell. The phenomenon is almost always silent during its existence, with sound only at the moment of disappearance. Roughly 5% of the population claims to have witnessed ball lightning, making it rare but far from unknown.