Definition of “°F”
“°F” is a unit of measurement used to express temperature in Fahrenheit scale. Fahrenheit scale is commonly used in the United States for weather forecasting, cooking and household purposes. It is based on the freezing point of water at 32°F and the boiling point of water at 212°F, with a difference of 180°F between the two points.
In the context of altitude, as pressure and temperature decrease with increasing altitude, the standard lapse rate for temperature in the lower atmosphere is approximately 2°C (3.5°F) for each 1,000 feet of altitude. Therefore, when calculating the temperature at a certain altitude above mean sea level (MSL), the standard temperature at MSL is adjusted by subtracting 3.5°F for every 1,000 feet of altitude. This adjustment factor of 3.5°F is equivalent to 2°C, which is used in calculating the standard temperature lapse rate.
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