Definition
A unit of temperature measurement on the Fahrenheit scale, in which water freezes at 32 degrees and boils at 212 degrees at standard sea level pressure. Written as °F.
Plain English
A way of measuring how hot or cold something is. On this scale, freezing water is 32 and boiling water is 212.
Context Anchor
Seen in aviation weather, aircraft manuals, performance charts, and test questions when temperature is shown as °F.
Derivation
Named after Daniel Gabriel Fahrenheit, the 18th-century German physicist who developed the scale. Knowing it's a person's name helps explain why the scale's reference points (32 and 212) seem arbitrary — they reflect his original calibration choices, not round numbers.
Why Pilots Care
Many U.S. aircraft instruments, charts, and weather products use Fahrenheit, while international and technical aviation data often use Celsius. Pilots need to read both and convert when required for performance calculations.
Grounding Statement
A reading of 86 degrees Fahrenheit means a warm day, not an angle or compass direction.
Intuition Check
Degrees here are temperature units, not angle or compass degrees. Also, °F is not the same as °C; the same number on the two scales means a different temperature.
Example Sentence 1
The outside air temperature gauge read 45 degrees Fahrenheit before takeoff.
Example Sentence 2
During preflight planning the reported temperature was 28 degrees Fahrenheit, so the pilot verified that anti-ice equipment was functional.