***Link*** :: [Chapter 12: Weather Theory](https://www.faa.gov/sites/faa.gov/files/regulations_policies/handbooks_manuals/aviation/phak/14_phak_ch12.pdf) ***Description*** :: `= this.link` ***Author*** :: [[FAA]] ***Key Quotes***: * Weather is an important factor that influences aircraft performance and flying safety. It is the state of the atmosphere at a given time and place with respect to variables, such as temperature (heat or cold), moisture (wetness or dryness), wind velocity (calm or storm), visibility (clearness or cloudiness), and barometric pressure (high or low). * This chapter explains basic weather theory and offers pilots background knowledge of weather principles. It is designed to help them gain a good understanding of how weather affects daily flying activities. #source #handbook/phak