Are they biting?

Bands. Each river’s bar is its own measured in-season daily flows (USGS) on a log scale, because a change from 50 to 100 ft³/s looks as big on the water as one from 500 to 1,000. Very low and blown out are its lowest 5% and highest 3% of days. The sweet spot is the band where Cleveland Metroparks’ weekly reports, in our reading of their words, usually described the Rocky River as in good shape: about 111 to 492 ft³/s there. Other rivers get the same slice of their own usual flows (their 39th to 83rd percentile days); that part is untested, because the reports describe the Rocky.

How well the sweet spot matched the reports. Of 146 reports, 64 stated a condition we could sort and had a measured flow. Fitted on all but one season and checked on the one left out, the band matched our label 49 times out of 64; always guessing “good” would match 35. Rotating each season’s labels by a random number of weeks, 200 times, the highest-scoring run matched 43.

Direction compares the last measured day with the day two before it (up 15% or more is rising; down by the same ratio is dropping). Drop-back times count days from each past peak above the sweet spot to the first day back in it, from USGS daily means. Water temperature compares that day with the middle half of past readings within a week of the same date. Days like today are the Rocky report days whose flow the day before, and its direction, came closest to today’s.

None of this counts fish, clarity, ice or fishing pressure. Moon phase isn’t used.