Start with Diawl Bach (12-14) — on the bob / top dropper — slow figure-of-eight retrieve. Rainbows respond to more active retrieves — try short strips between pauses. If that does not produce, switch depth or speed before changing the pattern entirely.

Fish early and late, try deeper during the heat of the day with a fast-sinking line.

Evening tends to be the best period in summer — stay late if you can for a sedge or spinner fall.

Bank-only venue. Fish from accessible margins, points, weed edges, and inflows.