What temperature defines a cold soaked wing?

A cold soaked wing is defined as one that has been exposed to low temperatures, typically below freezing. Temperatures below 0°C (32°F) result in the wing's surface staying cold, which can affect the aircraft's performance and require careful pre-flight inspections, especially concerning ice formation. In contrast, temperatures above this threshold may not pose the same risks associated with ice accumulation.

When considering other options, temperatures below 10°C (50°F) do not necessarily indicate a cold soaked condition, as the critical point is 0°C (32°F). Similarly, temperatures between 0°C and 5°C may still be within a range where ice could potentially form on the wing, but would generally not be classified as "cold soaked" since they aren't below freezing. Thus, the defining temperature for a cold soaked wing is indeed below freezing, making it a crucial threshold in aviation safety and maintenance practices.