What is the Fahrenheit scale?

Fahrenheit (°F) is a temperature scale where water freezes at 32°F and boils at 212°F at standard atmospheric pressure. The 180-degree span between these points (compared to 100 in Celsius) gives Fahrenheit finer granularity for weather temperatures.

Why does the US use Fahrenheit?

The US adopted Fahrenheit in the colonial era when it was the dominant scale in the English-speaking world. While most countries switched to Celsius during metrication in the 1960s-70s, the US never completed that transition. The familiar scale persists through cultural inertia.

Daniel Fahrenheit originally set 0°F as the temperature of a specific brine (salt/ice/water) mixture, which was the coldest temperature he could reliably reproduce in his lab. It equals approximately -17.78°C.

What Is Fahrenheit? Temperature Scale Definition & History

Definition

The Fahrenheit scale (symbol: °F) is a temperature scale with these reference points:

32°F: Freezing point of water
212°F: Boiling point of water
98.6°F: Normal human body temperature

Fahrenheit Weather Guide

°F	°C	Conditions
0	−18	Dangerously cold
32	0	Freezing, ice/snow
50	10	Cool, jacket weather
60	16	Mild
70	21	Comfortable
80	27	Warm
90	32	Hot
100	38	Extreme heat

History

Daniel Gabriel Fahrenheit (1686-1736), a German-Dutch-Polish physicist, introduced his scale in 1724. He used three reference points: 0°F for the coldest brine mixture, 32°F for ice water, and 96°F for body temperature (later refined to 98.6°F). His mercury thermometer was more accurate than earlier instruments.

Advantages of Fahrenheit

Proponents note that Fahrenheit's 0-100 range roughly maps to the range of outdoor temperatures humans experience. A day at 0°F is bitterly cold; a day at 100°F is extremely hot. This makes the scale intuitive for weather, even if Celsius is more logical for science.

Conversion Formula

°F to °C: °C = (°F − 32) × 5/9
°C to °F: °F = (°C × 9/5) + 32
Where they meet: −40°F = −40°C

Convert temperatures with our temperature converter.