What Is Freezing Point in Fahrenheit? A Plain-Language Guide
The freezing point of pure water is 32 °F at standard atmospheric pressure. This is the same temperature as 0 °C. At that pressure, water boils at 212 °F, so the interval from freezing to boiling is 180 Fahrenheit degrees Wikipedia — Fahrenheit.
Why water freezes at 32 °F
The Fahrenheit scale was proposed by Daniel Gabriel Fahrenheit in 1724 Wikipedia — Fahrenheit. In his original scale, 0 °F was based on the temperature of a mixture of ice, water, and ammonium chloride. It was not the freezing point of pure water. Pure water freezes higher on the scale, at 32 °F.
For many years, the scale was described using water’s freezing and boiling points at standard atmospheric pressure: 32 °F and 212 °F. The difference between those temperatures is 180 °F. The scale is now defined in relation to the kelvin, but 32 °F remains the familiar reference for water freezing.
A Fahrenheit degree represents a smaller temperature interval than a Celsius degree. A change of 1 °F equals a change of 5/9 °C, or 5/9 K. This describes a difference in temperature, not the conversion between two temperature readings. To convert a temperature in Fahrenheit to Celsius, subtract 32 and multiply by 5/9.
One example
If a thermometer reads 32 °F, it reads 0 °C. Under standard atmospheric pressure, that is the freezing point of pure water. In outdoor conditions, a reading of 32 °F does not guarantee that every surface will freeze: local conditions and the temperature of the surface matter.
Key Takeaways
- Pure water freezes at 32 °F, or 0 °C, at standard atmospheric pressure.
- At the same pressure, water boils at 212 °F. The difference between its freezing and boiling points is 180 °F.
- Fahrenheit’s original 0 °F referred to a brine mixture, not pure water Wikipedia — Fahrenheit.
- A change of 1 °F equals 5/9 °C. To convert a Fahrenheit temperature to Celsius, subtract 32 and multiply by 5/9.
