Just something I thought up.
Suppose for a second that Finland is somehow able to avoid getting into the Continuation War with the USSR and remains neutral throughout World War II. Then at some point, Stalin decides to order a landing on Kirkenes in northern Norway as a kind of Soviet "Dieppe" in order to spook Hitler and cause him to divert precious manpower from the Eastern Front.
What would be the window for such a landing? Would it be, say, February to October? From October to late January I would imagine that the weather would be a bit too rough for such an operation. Also there's the polar night to consider.