How hot is a lightning bolt, in degrees Celsius?
Guess before you scroll — the answer is below
The answer
30,000 degrees Celsius
Roughly 30K.
A lightning channel reaches about 30,000°C — roughly five times hotter than the surface of the Sun. The thunder you hear is the air around it exploding outwards from being heated that fast.
How to get close to this number
The cue is in the sound. Thunder is not the bolt; it is the air around the bolt exploding outward because it was heated faster than it could get out of the way, as the explanation says. Anything that can make air detonate is not merely hot in the domestic sense — it has to be far past the temperature of a flame, which pushes the estimate into tens of thousands of degrees rather than thousands.
The intuition most people fall back on is fire, and fire is the wrong reference. A candle, an oven and even a furnace all live in a range that lightning leaves far behind. The comparison in the explanation — several times the temperature of the Sun's surface — is the one that recalibrates the scale, and it is the single most surprising thing about the figure.
Worth being precise about what is hot: the channel itself, for a few tens of microseconds, and not the surrounding air or anything the bolt strikes. That is why lightning can leave a tree scorched rather than vaporised, and why the temperature is inferred from the light the channel emits rather than measured with any instrument placed in it. It is a spectroscopic estimate, which is why it is quoted as a round approximate figure.
Where this number comes from
| Source | National Oceanic and Atmospheric Administration |
|---|---|
| Figure refers to | 2024 |
| Last checked | |
| Unit | degrees Celsius |
Numbers move. If this one has drifted from its source, let us know.
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