This has most likely been discussed, and I'm not sure if this is the right section to post this question, but here goes it...

After several weeks of excessive heat and no rain, We've finally got a break in the summer doldrums. The concern now is that it's rained continuously for two days. Surprising, the pond has only received about two inches of new water from runoff and rainfall. It has stayed remarkably clear as well. Prior to the change in weather surface temps had crept into the mid to upper 90s. My question is...

Without aeration, how cool does the surface water need to get before it's dense enough to sink and create a turnover. I'm thinking this could be pretty detrimental to every fish in the pond.

Never seems to be a happy medium to our weather. Luckily, I don't think it's a really cold rain as temps are staying in the 80s during the day and 70s at night.

Cloudy days and rain during summer ,like that caused by tropical storms can cause turnover. It is often caused by stuff washing in , dissolving and taking the O2 out. Temp is not the issue when going from 90+ to 75. Low O2 is the problem. Surface aeration can be used if you become concerned. Because the cool water will sink anyway (and have O2) don't be concerned with aerating deep water in this situation. Be sure the top 3 feet have O2 no matter the temps.

Thanks for the wisdom Mr.West.

I just got home and the pond is now back to full pool again and going out the overflow. Surprisingly enough, it's still clear and the water flowing in doesn't appear to have any color to it at all. Flowing in from my neighbors property, it flows above ground probably 60 feet. I feel like what's coming in is being pretty well saturated with O2. Being that it's coming in clear, and I doubt seriously my neighbor does any fertilization or herbiciding, I think we'll be fine.

Thanks again.

The rain let up so I went out and checked the surface temp. Amazed it only fell to 80*.

Welcome - keep an eye out and be ready to stir up the water if the circumstances require it. Sounds like all is ok.