This claim is widely established, but this scan retrieved limited high-authority sources. Confidence was held to a reasonable level without marking the claim as disputed.

Verdict TRUE

TRUE — Does Water Always Boil at 100°C?

Verified on April 2, 2026

While 100°C is the standard boiling point at sea level, it changes with altitude. On a mountain, your tea might boil at just 71°C!

Confidence72%

How strongly independent, cited sources support this verdict.

Analysis summary

Water boils at 100°C at standard sea-level pressure, but this temperature fluctuates significantly depending on atmospheric pressure and altitude.

Evidence profile

Key findings

Water boils at exactly 100°C (212°F) only at standard atmospheric pressure (1 atmosphere), which is typically found at sea level.
The boiling point of water decreases as altitude increases; for example, on Mount Everest, water boils at approximately 71°C (160°F) due to lower air pressure.
The Celsius scale was originally defined by the freezing point (0°C) and boiling point (100°C) of water at sea level, though modern scientific definitions use the triple point of water for higher precision.

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TRUE — Does Water Always Boil at 100°C?

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