-21 Celsius to Fahrenheit
-21 degrees Celsius equals
-5.8°F
-5.8 degrees Fahrenheit
-21°C is -5.8°F, well below the point where water freezes. Roads ice over here, and this is where winter forecasts in northern climates spend most of the season. For reference, water freezes at 0°C, or 32°F.
How to convert -21°C to °F
Formula
°F = °C × 9/5 + 32
Substituting -21°C
- -21 × 9/5 = -37.8
- -37.8 + 32 = -5.8
The two scales differ in both their zero point and their step size. A Fahrenheit degree is 5/9 the size of a Celsius degree, and the scales are offset by 32 degrees at the freezing point of water — which is why the conversion needs both a multiplication and an addition.
How -21°C compares
| Reference point | Temperature | Difference |
|---|---|---|
| Freezing point of water | 0°C / 32°F | 21°C (37.8°F) colder |
| Room temperature | 21°C / 69.8°F | 42°C (75.6°F) colder |
| Body temperature | 37°C / 98.6°F | 58°C (104.4°F) colder |
| Boiling point of water | 100°C / 212°F | 121°C (217.8°F) colder |