What is a Fahrenheit?

Fahrenheit is the everyday temperature scale in the United States, used for weather, cooking, body temperature, and HVAC settings. Proposed by German physicist Daniel Gabriel Fahrenheit in 1724, it set 0°F as the lowest temperature he could reliably reproduce (a brine-ice mixture) and 96°F as human body temperature. Modern definitions place water's freezing point at exactly 32°F and boiling at 212°F — making the freezing-to-boiling range exactly 180 degrees. The Fahrenheit scale was the international standard for English-speaking countries until the UK and Commonwealth nations switched to Celsius in the 1960s and 70s. Today the United States is the only major industrialized country still using Fahrenheit for weather. A comfortable room is 68–72°F, fever begins at 100.4°F, and Death Valley summer highs reach 120°F. Fahrenheit relates to Celsius by °C = (°F − 32) × 5/9.

Visual reference for how the fahrenheit relates to other temperature units. Each row links to the full converter for that pair.

• US daily weather and climate reports
• US cooking oven temperatures
• US medical thermometers

• ✓Formula: °F = (°C × 9/5) + 32.
• ✓Rough conversion: subtract 30 then halve to get °C. 70 °F → 20 °C.
• ✓US ovens in °F; European ovens in °C. Convert before starting a foreign recipe.

• ✗Using °F readings in European contexts without conversion.
• ✗Forgetting the +32 offset — a 20 °F rise is not 20 °C rise.
• ✗Assuming 50 °F is half of 100 °F in feel — in °C it is 10 °C vs. 38 °C.