What is a primary characteristic of wet snow at flight altitude?

The primary characteristic of wet snow at flight altitude is its association with temperatures above freezing. Wet snow occurs when snowflakes partially melt as they fall through a layer of warm air, typically found in conditions where the temperature is slightly above the freezing point. This results in heavy, moist snow that can adhere to surfaces, creating potential hazards for aircraft, such as reduced lift and increased drag.

In contrast, the other options involve different weather phenomena or conditions that do not directly relate to the characteristics of wet snow. High winds can occur with various types of precipitation but are not characteristic specifically of wet snow. Clear skies typically denote stable weather conditions, which would not support the formation of wet snow at flight altitudes, as this precipitation usually requires clouds and moisture. Low visibility can occur in snowy conditions, but it is a consequence of precipitation rather than a defining characteristic of wet snow itself. Therefore, the link between wet snow and temperatures above freezing is what makes it the most accurate choice in this context.