Formulas and reference points
- °F = °C × 9/5 + 32 and °C = (°F − 32) × 5/9
- Water freezes at 0 °C = 32 °F and boils (at sea level) at 100 °C = 212 °F
- Body temperature is about 37 °C = 98.6 °F. A fever usually means 38 °C (100.4 °F) or more.
- Ovens: 350 °F ≈ 177 °C and 180 °C ≈ 356 °F
- −40 °C and −40 °F are the same temperature.
For a rough mental conversion, double the Celsius value and add 30 to get Fahrenheit. The error grows at very high or low temperatures.