Why do cumulonimbus clouds most likely form on sunny days?

Cumulonimbus clouds typically form on sunny days because they require a strong upward movement of warm, moist air, which is common when the sun heats the Earth's surface. This heating causes convection, leading to the rising of warm air that cools and condenses to form these towering clouds. Additionally, sunny conditions often provide the necessary energy for the development of thunderstorms associated with cumulonimbus clouds. Thus, their formation is closely linked to the presence of intense solar heating.