It changes for me.
that said i either have terrible rain + visability, or perfect visability.
was expecting to encountera little variety inbetween.
I never really notice it, the weather ussually sets in whilst im submerged.
only time i ever noticed real time change is when i was engaging a task force with 2 kongo's and a Yamoto ( my first sighting
)
flaming fog rolled in as i was making my aproach.
that damned Yamoto had a force field too. 3 torps in the morning, 2 torps the next evening, all blew up before they could reach it. talk about bad luck