Celsius vs Fahrenheit
Updated 2026-01-10
Where the two scales come from
Celsius sets 0° at the freezing point of water and 100° at its boiling point at sea level, making it a naturally intuitive scale for most everyday weather. Fahrenheit, developed earlier, uses a different zero point and a finer-grained scale — water freezes at 32°F and boils at 212°F. Most of the world uses Celsius for weather; the United States is a notable exception that still uses Fahrenheit.
Converting between them
The exact formulas are °F = (°C × 9/5) + 32 and °C = (°F − 32) × 5/9. For a fast mental estimate, doubling a Celsius value and adding 30 gets you roughly close to Fahrenheit for everyday weather temperatures — accurate enough to decide what to wear, though not precise enough for scientific use.
Useful reference points
A few points worth memorizing: 0°C (32°F) is freezing, 20°C (68°F) is a mild room temperature, 30°C (86°F) is a hot day, and 37°C (98.6°F) is normal human body temperature. WeatherIQ lets you switch the whole site between °C and °F at any time using the toggle in the header.