Don’t clouds also retain heat from the ground so less clouds means colder nights?
No, I think we all say it is a component. Just that the other components are in balance or not so important on the timescales that we look at. On larger and smaller timescales, they are also relevant (especially on larger ones).
It is perpetually cool in Seattle because of the excessive cloud cover and the cold equatorward moving ocean currents along the West Coast. It gets warm when a high pressure system builds over the Pac NW, giving you a temporary break from the cloud cover. I am sure Seattle also gets down sloping (adiabatic) winds to warm and clear their skies at times.
Well now, that is yet another parameter thrown into the climate mix - orbital variations.
It is at the wrong concentrations. Just like most anything else.
We have very little CO2 in the atmosphere based on the paleoclimate time scale.
The Northeastern US is colder in the winter than the Northwestern US because mid-latitude weather systems move from west to east. Frontal systems bring Continental Polar air across the Northeast, which is substantially colder than the Maritime Polar air frontal system bring to the Pac Northwest.
You have your head fixed on land. You are forgetting most of the earth's surface is ocean. There is not a one to one correspondence between short-wave radiation coming into the ocean vs. long-wave radiation going out. Less clouds warms the oceans, which in turn warms the earth.
