ATPL Meteorology Test 2026 – 400 Free Practice Questions to Pass the Exam

For freezing rain (FZRA) and drizzle (DZ) formation, the essential condition is that the droplets must be supercooled or near 0°C. Supercooled water refers to liquid droplets that remain in liquid form below the freezing point, typically around 0°C. This supercooling occurs when these droplets are suspended in an environment where they do not have a nucleus or surface to crystallize upon.

As these supercooled droplets come into contact with colder surfaces, such as roads or aircraft wings, they freeze on contact, leading to the formation of freezing rain. This condition is crucial because if the droplets were not supercooled, they would freeze before reaching the ground, resulting in different types of precipitation, such as snow.

The requirement for supercooled conditions distinguishes freezing rain from other types of precipitation, emphasizing the unique atmospheric dynamics that allow for such droplets to exist and eventually lead to the icing hazards associated with flight operations and road conditions.