cb,

In Northern OK, we began seeing CC in the rocks by the last week of May. By the third week of June, they would be mostly gone. So I think our peak was during the first two weeks of June. If water temp is the primary driver, then that would put initiation at around 72-73 F and peak at around 75-76 F (here using daily average air temperature as the source of temperature). Not sure if that helps but anticipating a little before those temps are reached in your locale and watching a few weeks may help you determine the season there.

It isn't what we don't know that gives us trouble, it's what we know that ain't so - Will Rogers