Water Temperature Lake Chapala

I haven't been able to find any stats as to the average water temperature over the year for Lake Chapala. I like 'aquajogging', there is a large, beautiful pool here but it has no heating whatsoever. I am buying an inexpensive quality scuba suit, but I have to figure out what size fabric to order - I think the Lake temperature would be a good guide, except the pool will become much hotter in the summer - not a problem. Has anybody ran across this info or measured the temperatures of an unheated pool?
Gary, not Lesley