When a U.S. forecast says "70°F," it may be hard to tell how warm that is. Celsius and Fahrenheit are not directly proportional; they are connected by the linear relationship F = 1.8×C + 32. Move the slider to explore it.
Celsius (°C)20
F = 1.8 × C + 32
1.8 × 20 + 32 = 68°F
Freezing point of water: 0°C = 32°FBoiling point of water: 100°C = 212°FHuman body temperature: about 37°C = 98.6°F
Why the formula looks this way: Water freezes at 0° Celsius but 32° Fahrenheit, and boils at 100° Celsius and 212° Fahrenheit. The line through (0,32) and (100,212) has the equation F=1.8C+32 — exactly a linear-function graph.