I really never pay much mind to water temps when I am fishing for whites. I have noticed that the kind of fishing I do is much more related to cold fronts with pre spawners.
For example, I caught many on Tuesday but couldn't go back on Wednesday. I had to go today to take my best friend who couldn't go any other day this week. To get to the point, after last night's cold front, the two of us didn't catch 20% of the fish I caught by myself on Wednesday and the water was 3° warmer.