−5 °F at a glance
- Celsius
- −20.56 °C
- Exact fraction
- −20 5/9 °C
- Kelvin
- 252.59 K
- Rankine
- 454.67 °R
- Rounded
- −21 °C
- Quick estimate
- −17.5 °C
How to convert −5 °F to Celsius
(−5 − 32) × 5/9 = −37 × 5/9 = −185/9 = −20.56 °C
Subtract 32 first because the two scales put zero in different places, then multiply by 5/9 because a Fahrenheit degree is only 5/9 the size of a Celsius degree. −37 is not a multiple of 9, so the exact answer is the repeating decimal −20 5/9 °C.
Estimate it in your head
Subtract 30 and halve: (−5 − 30) ÷ 2 = −17.5 °C. That is 3.1 degrees high — the shortcut drifts at very hot and very cold temperatures, so use the exact formula there.
What −5 °F feels like
Below zero Fahrenheit, wind matters more than the thermometer. The National Weather Service wind chill index estimates how cold −5 °F feels on exposed skin; once the wind chill reaches about −18 °F (−28 °C), frostbite can set in within 30 minutes.
| Wind | Feels like | In °C | Note |
|---|---|---|---|
| 10 mph | −22 °F | −30 °C | Frostbite possible in 30 min or less |
| 20 mph | −29 °F | −34 °C | Frostbite possible in 30 min or less |
| 30 mph | −33 °F | −36 °C | Frostbite possible in 30 min or less |
At −20.56 °C even a home freezer (0 °F) would feel warm. Car batteries lose much of their cranking power, diesel fuel can gel without additives, and pipes in unheated spaces are at real risk.
Temperatures near −5 °F
| Fahrenheit | Celsius | Kelvin |
|---|---|---|
| −10 °F | −23.33 °C | 249.82 K |
| −9 °F | −22.78 °C | 250.37 K |
| −8 °F | −22.22 °C | 250.93 K |
| −7 °F | −21.67 °C | 251.48 K |
| −6 °F | −21.11 °C | 252.04 K |
| −5 °F | −20.56 °C | 252.59 K |
| −4 °F | −20 °C | 253.15 K |
| −3 °F | −19.44 °C | 253.71 K |
| −2 °F | −18.89 °C | 254.26 K |
| −1 °F | −18.33 °C | 254.82 K |
| 0 °F | −17.78 °C | 255.37 K |
Going the other way: −21 °C in Fahrenheit is −5.8 °F.
Frequently asked questions
What is −5 °F in Celsius?
−5 °F is −20.56 °C: subtract 32 (−37) and multiply by 5/9.
Is −5 °F hot or cold?
−5 °F is severe cold, 5.0 degrees below zero Fahrenheit and well below freezing.
How do you convert −5 °F to Celsius in your head?
Subtract 30 and divide by 2: (−5 − 30) ÷ 2 = −17.5 °C, compared with the exact −20.56 °C.
What is −5 °F in Kelvin?
−5 °F is 252.59 K. Convert to Celsius (−20.56 °C) and add 273.15.