The season
SolidThe season & the hatch year
The trout's year runs on a predictable procession of hatches — get the month right and you're fishing the food that's actually on the water.
Why
Fly hatches are driven by temperature and daylength, so they arrive in much the same order every year. On the big Irish limestone loughs the year runs: duckfly building through March and April; lake olives from late April; the famous mayfly from around the third week of May for about a month; sedges — the Green Peter and murrough — from July into the warm evenings; and the daddy-longlegs and dapping into the back-end from mid-August.
Trout key hard onto whatever is hatching in numbers, often ignoring everything else. Matching the month's hatch — pattern, size and the way it behaves on the water — is usually worth more than any clever retrieve.
The season also sets the daily rhythm from the other cards: cold spring water means a midday game; warm high summer means dawn and dusk; the mayfly and sedge weeks bring fish up in the day.
On the water
- Fish the hatch that's actually on — check what's coming off the water and in the air before you tie on.
- In warm high summer the sedge fishing is an evening-and-after-dark game; in cold early spring the duckfly is a middle-of-the-day one.
- Always check the season dates and local rules with the fishery — a hatch and an open season are not the same thing.
The numbers
- Duckfly
- Mar–Apr
- Mayfly
- late May, ~1 month
- Sedge / Green Peter
- Jul on, evenings
How LoughLogic uses this
The app carries a per-water hatch calendar, and the outlook gives a small nudge to windows in a water's hatch months — the season shaping the same score the conditions do.
How sure are we?
Solid. Hatch timing on the Irish loughs is well documented and observable year on year; the exact dates shift a week or two with the spring's weather, which is why we tie advice to the month and the water, not a fixed date.
Related
Sources & how we know this (2)
- The Corrib olive and mayfly hatch runs from late April, with the mayfly from around late May for roughly a month.
Fly Fishing Ireland — the olive and mayfly hatch on Lough Corrib · 2026-07-16 - Irish game-angling seasons and hatch progression through the year (Fishing in Ireland).
Fishing in Ireland — trout fishing guidance · 2026-07-16