Precipitation
Precipitation is a core knowledge area on the Aviation Weather FAA written exam. This hub collects our 5 in-depth, ACS-aligned precipitation articles — each written in plain English and grounded in the official FAA handbooks. Work through them below, then drill the topic with practice questions.
How Raindrops Grow: Collision-Coalescence and the Ice-Crystal Process
Cloud droplets are too small to fall as precipitation on their own; two growth processes—collision-coalescence and the ice-crystal process—explain how droplets and crystals grow large enough to reach the ground, determining the type of precipitation that forms.
Precipitation Types: Rain, Snow, Ice Pellets, and Freezing Rain
Precipitation forms through two growth processes and occurs as rain, snow, ice pellets, freezing rain, or hail depending on the vertical temperature profile — a critical concept for flight safety and weather-related test questions.
Hail Formation and Why It Signals Severe Thunderstorms
Hail forms inside severe thunderstorms when supercooled water freezes and accumulates around ice nuclei; it signals extreme updrafts, great storm height, and poses one of aviation's most dangerous inflight hazards.
Ingredients for Precipitation: Moisture, Lift, and Nuclei
Precipitation requires three key ingredients—moisture, lift, and condensation nuclei—plus growth processes that build droplets large enough to fall; understanding these explains every precipitation type from rain to hail.
Freezing Rain and the Temperature Profile That Creates It
Freezing rain demands a specific temperature sandwich: a deep warm layer aloft melts snow into rain, then a shallow subfreezing layer at the surface allows drops to reach the ground still liquid — and freeze on contact with anything they touch, including your aircraft.
More Aviation Weather subjects
Articles are original summaries grounded in the public-domain FAA handbooks and cite their source. ACS-aligned study aids — not a substitute for the official handbooks or regulations.