jan siepelstad wrote:
Hello,

I'm looking for a place, where I can find the hours/amounts of diffuse and
direct insolation in the Netherlands during wintermonths.

Anyone any idea where to look?

All sunlight?

A nautical almanack. It will be the same eery year and the lunar input
will be the same too on average. So just add in reflections and
refraction from the moon and noctilucent cloud.

The cloud bit will be the bugbear but at least you will be aware of the
problem -which is more than you can say for not a few environmentalists
and glowballers. They don't seem to be able to grasp that clouds carry
a tremendous amount of heat to regions where it can be shed from the
earth most easily.

The sad bstds.