I understand that sometimes the temperature stays warm on cloudy days, it does the same thing here in U.S. but this is not because of the sun. Its because of atmosphere. Sometimes in the winter time here in the Midwest the air temperature is actually colder on sunny days. What does it mean? Well it means that the winter sun is weak. If the sun truly was the way science tells us it is, it would bring consistent high temperatures whenever its out. Yet the winter sun does not warm anything up. So this means that sun is small in comparison to earth. In the summer time it gets warmer because sun moves closer to the earth in northern hemiplane.
Any/all warming of the earth's atmosphere, and the planet itself is due solely to the radiation emitted by the sun.
Whilst the
apparent air temperature may well be colder on a clear sunny day, and warmer on an overcast day, the earth's core temperature remains (relatively) constant. You have to exclude any localised ground effects on air temperature at the earth's surface—such as the "heat bank" effect in large cities, or the cooling effect in heavily vegetated rural areas.
There is no such thing as a "weak" sun. The sun releases exactly the same amount of radiant energy each and every day of the year.
And try and tell people living on the equator that the winter sun doesn't warm anything up LOL. The temperature in Pontianak, in Indonesia (for example) never drops below 82ºF even during winter.
And no; it doesn't get warmer in summer because the sun moves closer to the earth—the sun does
not "move" relative to the earth (or any other body for that matter; it's stationary).
Check out this diagram for the science of seasonal temperatures: