How can lightning heat air so intensely?
A tiny path of electrically heated air can briefly become hotter than the Sun’s visible surface.
A sudden electrical discharge
Thunderstorms can separate electrical charges within clouds and between clouds and the ground. When an electrical breakdown occurs, current travels through an ionised path in the air. Energy is released very rapidly into that narrow channel, and temperatures can briefly reach tens of thousands of degrees Celsius.
The shock wave we call thunder
The extreme heating makes the air expand suddenly. That expansion generates a pressure wave, which travels outward as thunder. Light reaches our eyes much faster than sound reaches our ears, so we normally see a flash before hearing the rumble.
A comparison with an important limit
The lightning channel may be hotter than the visible surface of the Sun, but it is extremely narrow and short-lived. That comparison does not mean a storm contains more total heat than the Sun. Understanding the scale, duration and mechanism is essential when comparing temperatures. Lightning remains dangerous even when a strike looks distant, so seeking substantial indoor shelter during a storm matters.
External references are provided for exploration; Curio Hour’s explanation is written separately.