Visibility - what affects it?

    Ok, I am new to the diving thing and living close to the ocean in general. Here is my question(s):


    What different things cause bad visibility in an area with otherwise good visibility? What sort of things do you look for when attempting to estimate what visibility is going be like for a given day?


    My observations so far: Rain = bad. Wind/chop = bad. Swell = bad. I've also noticed that certain areas always have lower visibility, but some spots will suddenly open up and I can see 100ft. Is it bottom strata/composition? Something else? I've also noticed that visibility seems better, overall, in the morning and drops noticeably by the afternoon.

    i am a new to spearfishing as well but from what my father told me , alge has a part to play . alge population can grow due to nutrients from near by fresh water rivers , industrial run off . the only thing i can think of for the difference between morning and afternoon is the greater winds druing the afternoon due to the sun's heat , stirring up the water.

    Be safe ... Happy hunting .

    size of the sand on the bottom. If it's really silty/fine then it will take longer to settle after a storm. If its more coarse, it will settle in the water column easier.


    Currents in the area will clean out the dirty water faster which is why the SE coast of FL has better viz than the Gulf.


    In hot water with lots of sunlight the viz will be better in the AM than the PM because of the algae that grow in the top 15ft of water


    In the Caribbean, tall islands (mountainous) will have poorer viz than flatter islands because there will be more runoff from the rain. This is why the Bahamas has such clean water, but islands like Grenada have only 40ft of viz on a normal day.


    Rivers near the area will dump dirty freshwater into the areas surrounding creating very poor vis.


    Tides coming out of estuaries will also affect the viz as the dirtier estuary water is being dumped out on an outgoing tide.


    THats all I have off the top of my head, but if I think of more, i'll let you know

    That makes sense. I'd been told the rains affected it a lot, and we've had an abnormally rainy fail and winter here (from what I've been told). I imagine we are closer to Granada in composition than the Bahamas (very few sand flats, mountainous terrain and rapid drop-off in a lot of areas).


    I am just trying to get it figured out, because it was relatively calm one day and the vis was bad, and windy another day and it went from 50ft of vis down to about 20ft by mid-afternoon in some spot. I am also realizing that as I get more comfortable in low vis, I am realizing the benefits of being able to approach fish more closely.

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