Standard conditions are used to compare current weather conditions to a known value - this can be very useful for pilots when performing performance calculations These values can be found in the [Aviation Weather Handbook (page 4-6)](https://www.faa.gov/sites/faa.gov/files/FAA-H-8083-28_FAA_Web.pdf#page=72) ## Standard Temperature $15 \degree$ Celsius or $59 \degree$ Fahrenheit ## Standard Pressure $1013.25$ Millibars or $29.92$ Hg (inches of mercury) ## Standard Lapse Rate $2 \degree$ Celsius per 1,000 ft and 1 inch of mercury per 1,000 ft