I was talking a friend "in the know" concerning Lake CDA's temperatures as reported on the website that momo linked to this site. It seems that the exact location where the official water temps are measured for that site are approximately 300 yards upstream from the IM CDA swim location, with the flow of water traveling towards, across and beyond the IM CDA swim location.
So, in other words, the temps from the official site are precisely the same as those at the IM CDA swim location.
I don't know if this info is actually helpful or not. Perhaps not if you were hoping that the water temps at the swim location were a bit warmer.
P.S. The lake water temps seem to be as volatile as recent financial market activities.