The method for determining river temp goes something like this:
Determine the average daily High temp over the last 4 days...... 27°
" " " " LOW " " " " " " ...... 14°
Add those two figures together, .................... 41°
Then divide by 2 ,...........................................20.5°
Hmmm. Well, by that theory it's either locked up in ice or its about 33-35°
The coldest water I have ever caught a limit of keeper bass in was 36° (just for trivial records sake). Lynch hollow at the 9mm.