The laptop display shows real world weather statistics from recent days. The monitor on the right shows my code, as I'm working on how sunshine affects temperature. Sure, in the night the temperature is lower, and on a sunny day it gets warmer - but how much? And, if the night sky is overcast, the temperature doesn't drop as much as it does if the sky is clear. All this has to be turned into functions and variables in my weather engine.

EDIT:
OK, I found a real world graph, which shows the average difference of night / day temperatures, per month. The blue line shows the values in Southern Finland, the red line is for Lapland. The graph on the left shows temperature difference when the sky is clear. And the graph on the right has values for cloudy weather. So, now I need to figure out an algorithm which would produce about same kind of curves.
http://blogi.foreca.fi/wp-content/uploads/2015/03/L%C3%A4mp%C3%B6tilavai...