So a clear winter’s night is just as warm as a cloudy one. Yeah right. The clouds hold in the heat. Like I said. They don’t block all wavelengths either. I’m not sure where you get your info from but a person can get sunburned on a cloudy day.
The morning after a clear winter night is colder than a cloudy one because the surface heat radiates out to space. Whether clouds have a net warming or cooling effect has more to do with their thickness than their altitude. Clouds are Earth’s iris and are the most significant factor in how much solar energy originally enters the oceans and climate. Human activity already influences them.