[Scoundreller]

Radiation is a function of the temperature delta between two points.

The sky around where clouds are might be around -20C, while outer space is at -273C or so, so you get much more radiative heat loss in the latter state (clear sky).

(This is also why you’ll see gardeners try to cover their plants when there’s a “frost warning” even though the temperatures won’t be going below freezing).

And from the opposite perspective, the sun is really far away but incredibly hot, so it transfers heat to us, and more as you get closer (and less as you get further away).