Pond Boss Forums GENERAL QUESTIONS Water chemistry Water Temp Question

Ok, so this is a dumb question that I couldn't find the answer to anywhere and unfortunately have to ask. What is the official way to take the water temperature of a pond/lake? Is there a standard depth that you use when you take a temperature reading, or can I just shoot a laser at the surface? There's a lot of articles out there that I'm reading that toss out temperatures but without any context, so that's leading me to believe there is some sort of standard way to take a measurement when talking about temperatures.

A question is never a dumb question especially when one cannot easily find the answer. The answer is really not a simple answer. Temperature of a water body regarding depth depends on numerous conditions and the reason why the water temperature is desired.

The water temperature of a pond or lake does usually change with depth and the conditions or time of year when the measurement is collected. Sometimes the temperature can sometimes vary by as much as 28F between top and bottom. When the water body is thermally destratified and being mixed by wind action (aka turnover), the temperature is mostly uniform (within 1-3 deg F) top to bottom. At other times during warm weather the water is usually warmest on top (6"-12") and within the upper 2 - 3 ft. Then at deeper depths the temperature decreases the deeper the temperature is collected. The amount of decrease depends on the type of water body, the depth and where the pond/lake is located. The amount of temperature decrease depends on the time of year, the exposure to wind action / height of vaves, the type of water body plus some other factors. All this is why you couldn't find a simple easy answer.

I assumed as much. I'm reading that BG start spawning at around 70 degree water temperature. When that number is tossed out there, at what depth would that be?

I love the infrared thermometer guns for solid radiating objects around the house or jobsite. They are certainly easy to use, especially to measure difficult to access areas.

However, I have never heard of anyone using them for pond temperatures. I think(?) a surface measurement at a pond might be heavily influenced by the evaporation rate, so you may be measuring pond temperature plus wind speed plus relative humidity, etc.

I have seen BG spawn in as little as 6" of water. However, if I was trying to observe the BG each year, I might create may own "standardized reference" for my pond. Maybe 2' deep off of the end of your dock? After a couple of years of data, you might be pretty accurate as to when you need to start looking for BG on the nest.

Water temperatures AND photoperiod control the spawning of many fish species. Since BG can spawn multiple times each year, they may not be quite as sensitive to photoperiod to start things off in the spring?

Hope that helps with some ideas behind your question.

I wouldnt worry about a thing you have no control over. If you need a temp just pick a spot and call it good.

I use a simple, cheap indoor/outdoor digital thermometer with the outdoor probe on a long (10' ?) cord. I personally just chuck the outdoor end into the pond from shore for a reading at 3' or so and then recheck at the surface, but one can easily drop it down from a small boat in measured increments for a detailed temp profile.

I guess just take the measurement the same way each time and call it a day.

Heck, take your infrared temperature gun with you and see if it does provide some useful information that correlates (somewhat) with your traditional thermometer readings.

Who knows, maybe people could use that device to observe the size and shape of the overturning water circulation cells around their aerators?

I used my infrared temperature gun today and compared it with a thermometer, it was within 2 degrees of the surface temperature.

Water temp is 54 degrees down to 5 feet. Didn't try to check any deeper. I figure my Tilapia are dying.