Pond Boss Forums INTRO Questions & Observations Cold affecting the Thermocline

There is no thermocline in winter. The thermocline is formed in spring months as the water warms. Since heat mostly rises (water is most dense at 39 degrees), warm spring temperatures and radiant heat from the sun push downward into the water. That heat can only go downward so far, assisted by winds and wave action. At that point, warm water rises to the surface and penetrates as far as its density allows. That's when the thermocline forms. It stays in place all summer and then as fall arrives, the surface water cools to the same temperatures as the lower water layer and the upper mixes with the lower, saying "adios" to the thermocline.
This time of year, the warmest water actually sits on or near the bottom, especially ponds that have ice cover.
But, there is no discernible thermocline to differentiate the warm bottom layer with the cooler surface water. It's a gradual change, simply because of the slighter difference in water density.