I'm with Steve.
The sun is the sun. When we judge "by eye" we are not really judging by eye (which truly is a very poor instrument as it adapts brilliantly to different light conditions) but inferring from experience. The sun is always the same. The sun above a certain angle, without clouds, is always the same in most of the photographer inhabited world. Yes conditions might be tricky above the Arctic Circles but generally speaking in Rome or in Buenos Aires the sun shines the same.