Tropical sun vs Western sun: another 80/20 rule

[Brunolem]

Here in Thailand, and most probably in other tropical countries, when clouds cover 80% of the sky, the sun still manages to shine 80% of the time.

 

That has actually been the case for many days lately...in some cases, the sun even manages to keep shining while it is raining, even strongly!

 

Meanwhile, back in Western Europe, when clouds cover only 20% of the sky, the sun can only manage to shine 20% of the time.

 

It is as if in some parts of the world, the sun was doing its best to keep us sweating, while in other parts of the same world it was doing its best to keep us freezing.

 

I guess there is a more scientific explanation for this phenomenon, or not?

[Ron19]

Closed, copied from topic running elsewhere.