[UKönig]

I have run into a similar situation from time to time.
A month and a half of terrible skies and towering waves with (sometimes) variable visibility. And yes, a lack of contacts during the same time.
I make up for that partially by moving to a harbour to attack anything at anchor or patrol offshore waiting for ships. They have to come by sooner or later...
It usually sorts itself out, but yes I think that's part of the bugs of the original game. The weather is inconsistent (and inconsiderate).