Experiencing thermal stratification in Bassenthwaite Lake

 

I took a dip in the lake on a lovely sunny day. I was confidently told that the water temperature was 19 degrees Celsius. As it happened, the water was noticeably warm but if I reached down more than 30cm, I could feel a cold layer below. It's been my introduction to thermal stratification. There is some interesting physics about how density differences result in different convection cells emerging. Also, that wind is the mixer that makes the layering break down as autumn arrives. It has been very windy here this summer so I'm interested to note that the layering still seems to exist.