Warm pool at night with steam/vapor?!?!

[endeavor]

I have a pool that has been above 80 degrees fahrenheit during the night (mainly because I have solar heating, and because I keep my pool cover on during the day). Recently I went for a swim just after sunset and noticed that I could see what appeared to be steam or some kind of vapor moving over or coming out of my pool. Now I thought it can't be steam, because steam is usually water in the form of vapor, which would have to be at 212 degrees fahrenheit! The air temperature is probably in the 60s at night, and I have a chlorine salt generating pool. Does anyone know what I am seeing and can anyone explain this to me?