lots and lots of "light fog"?

Just a question about weather in SH4. I'm running v1.5 with the latest official TMO (not the 1.8 beta). I have made several patrols now and I seem to be encountering a very high amount of "light fog" weather in the game. I don't know if this is designed to be realistic (I would imagine with the ocean having a lot of moisture fog might be pretty common) or a design choice to make things more challenging, or what? It is literally to the point where I don't think I have ever conducted combat in conditions other than light fog (and once in heavy fog). All the time that I operate in "real time" seems to always be in light fog, I am not sure what the conditions are all the time on the extended legs to and from Pearl Harbor which I run at high TC but random spot checks of these also seem to indicate a lot of fog.

does the amount of fog or probability for light fog depend on the geographical location or time of year? (aside: does the amount of daylight you get vary with latitude/time of year as well?) Maybe time of day too (where morning fog might be common but it dissipates in the afternoon when usually I am submerged or running high TC to cover ground)?

It's not really a complaint (other than the fact that the fog does slow the fps down a little) but just wondering is there supposed to be this much fog?

Ruahrc