-21 Fahrenheit to Celsius
-21 degrees Fahrenheit equals
-29.44°C
-29.44 degrees Celsius
-21°F is -29.44°C, 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°F to °C
Formula
°C = (°F − 32) × 5/9
Substituting -21°F
- -21 − 32 = -53
- -53 × 5/9 = -29.44
Fahrenheit places the freezing point of water at 32 rather than 0, so that offset comes off first. What remains is then scaled by 5/9, because a Celsius degree covers 1.8 times as much temperature change as a Fahrenheit degree.
How -21°F compares
| Reference point | Temperature | Difference |
|---|---|---|
| Freezing point of water | 0°C / 32°F | 29.4°C (53°F) colder |
| Room temperature | 21°C / 69.8°F | 50.4°C (90.8°F) colder |
| Body temperature | 37°C / 98.6°F | 66.4°C (119.6°F) colder |
| Boiling point of water | 100°C / 212°F | 129.4°C (233°F) colder |