why does winter have higher visibility underwater than summer?

title.

i think it is a common misconception that higher visibility is in summer as the weather is hotter than winter, but from my study i have seen this is false.
wondering why?

It depends on the area. But warmer water can result in more algae in the water with reduced visibility. Warmer weather
may also be associated with more rain and or run off that can also reduce visibility.

Up here in Puget Sound, the vis is usually much better in the winter than in the summer. We get a lot more light in the summer, which encourages plankton growth. Sometimes you'll have good vis in the summer as well, but that's usually after a few weeks after the plankton bloom.

Ron

It's simple really...more light + warmer water = a greater concentration of organic (living AND decaying) material in the water column. Less light + colder temps = less organics and better vis.

Remember, if anyone asks you "how was the vis on your dive?" Just say "as far as you could see!"

Less newbs silting up the joint?

fjpatrum:

Less newbs silting up the joint?

Click to expand...

That's cold.. ;-)

Nitro91:

title.

i think it is a common misconception that higher visibility is in summer as the weather is hotter than winter, but from my study i have seen this is false.
wondering why?

Click to expand...

While one can generalize based on water temps and daylight affecting plankton growth, it really is variable. Looking at some conditions that affect visibility in my local waters ...

- Summer months do mean more plankton ... at times, a LOT of plankton ... which can reduce visibility considerably. However, plankton growth occurs in cycles ... like all living things, plankton dies. When a die-off begins, it clumps together looking somewhat like strings of brown snot hanging in the water. The water between the clumps begins clearing up. As the plankton clumps die, they sink to the bottom, leaving some really clear ... beautiful visibility conditions until the next cycle begins. Depending on weather, this can be anywhere from a couple days to a week or so. This past summer I saw days where visibility was in excess of 50 feet ... a week later it was back to its usual 10-15 feet.

- Winter months do mean less plankton growth ... and generally better visibility. But winter also brings with it rain ... and stormwater runoff tends to put particulates in the water ... at times a LOT of particulates. Now the good news is that because these particulates are suspended within the stormwater runoff ... and because fresh water weighs less than salt water ... the really bad vis is often limited to the top 20-30 feet. Below that it might be dark, due to all that particulate matter and halocline condition filtering out the ambient light ... but it is relatively clear. A good dive light comes in handy.

- Spring brings snowmelt and flooding ... which pours a LOT of mud, as well as larger items, into the Sound. This can turn the water into a brown mess and reduce visibility to virtually zero. Again, because this is fresh water, it's not only less dense, but a lot colder than the salt water it's dumping into. Getting below it is usually the challenge ... ascents and descents in these conditions can become an exercise in how to maintain contact with your dive buddy ... because you sometimes won't see them even if you're holding onto each other.

Seasons affect visibility ... but sometimes other factors affect it even more ...

... Bob (Grateful Diver)

Could pollution from boat traffic and water use be a factor also?

For small inland bodies of water vis is generally better in the winter. Colder water means less plant life means better vis. This is true to a degree in the Ocean as well, but not always. For whatever reason the vis in FL tends to be worst in the winter This may be due to increased current or storms, I am not certain. Coz seems to have great vis year around likely due to deep water and strong currents. One thing for sure, there is not a thing I can do about it!

Beats me.