The Welsh Riverman's Hatch Guide

​A Month-by-Month Hatch Calendar for the Welsh Season

​The Welsh river season is a journey of transformation. From the biting winds of March to the golden, mellow evenings of September, the riverman must adapt his tactics to the shifting life cycles of the water.

 The season is a journey of transformation, from the rugged peaks of the North to the rolling valleys of the South. While every river is unique to its own area—meaning specific hatch timings can shift based on altitude, water temperature, and local micro-climates—the following patterns are the essentials. I have selected these to ensure you are covered for almost any situation you'll encounter.

By no means is this gospel and I would advice any angler to spend time on the water.

By no means is this guide gospel. In the world of fly fishing, everything is circumstantial; the river is a living, breathing entity that changes by the hour. These insights are born from years of dedicated time spent on the riverbank, countless hours of invertebrate sampling, and the hard-won experience of fishing my home waters

My best advice to any angler is this: use this guide as your starting point, but then go out and live the river. Spend time learning the rhythms of your own water, sample the bed, and map your fishing journey. The river is the greatest teacher we have.​

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MARCH 3RD OPENING DAY

The Awakening

This is the most anticipated part of the year for any fly fisherman in Wales. Just as the riverbanks begin to welcome the bright bloom of the daffodil, our national flower, the Welsh river angler also awakes from a winter slumber. Like the hardy daffodil pushing through the cold earth, we emerge in the early spring to face the elements.

Early season in Wales is dominated by a few hardy species. Look for activity during the warmest part of the day (usually 11:00 am – 2:00 pm).

• ​Key Hatches: Large Dark Olive (LDO), March Brown, Stoneflies.

• ​Observations: Large, mottled wings of the March Brown are unmistakable. LDOs trickle off in the cold.

• ​Fly Patterns: * Dry: Jingler (LDO), March Brown Upright, MB Emerger

  
  

  ​Wet/Nymph: March Brown Spider, Pheasant Tail Nymph (beaded if water is high).

  

  

  
  
  
  
  

April

The Big Duns

As spring takes hold, the intensity of the hatches increases a little more. April is famous on rivers like the Usk for the "Grannom hatch," which can turn the river surface into a carpet of small, dark sedges.

For me closer to home I look forward to the LBD (Large Brook Duns).

• ​Key Hatches: Grannom, Iron Blue Dun, Large Brook Dun, Olive Upright, LDO, LBD

• ​Observations: Clouds of Grannom fluttering upstream; the tiny, dark Iron Blue Dun appearing on rough, cold days.

  
  

• ​Fly Patterns:

  ​Dry: Grannom Sedge (with a touch of green at the tail), Iron Blue Dun. Large Brook Dun emerger. I use my March brown patterns to cover these as they are quite similar.

  ​Wet/Nymph: Snipe and Purple, Hare’s Ear Nymph.

  
  
  
  

​May

​The Smorgasbord

Widely considered the best month. The river is alive with variety, and the trout are in peak condition.

• ​Key Hatches: Mayfly (Danica), Yellow May Dun, Alder Fly, Hawthorn Fly (Bibio Marci).

  
  

• ​Observations: The majestic, large Mayflies dancing over the water; bright yellow splashes of the Yellow May Dun.

• ​Fly Patterns:

  • ​Dry: Mayfly emerger and Spent, Yellow May Dun, Hawthorn Fly (on windy days).

  • ​Wet/Nymph: Gold Ribbed Hare's Ear, Greenwell’s Glory.

  
  

​June

​The Evening Rise

As the days lengthen and the sun gets higher, the focus shifts to the dusk. The Magic of the Evening Rise, As the sun lingers longer over the Welsh valleys, we enter what is, for many of us, the pinnacle of the season. There is a feeling like no other when the workday ends; the frantic checking of the watch, the hurried messages to your fishing partner to compare notes on the wind and light, and that rush home to gather the kit. The anticipation builds with every mile driven toward the river, knowing that as the heat leaves the day, the water will come alive.

​These warm, long nights demand a change in soul and strategy. The heavier leaders of spring are replaced by long, fine leaders and diminutive flies. Success on the evening rise is a game of stealth and patience, waiting for that first sip of a rising trout against the sunset’s reflection.

• ​Key Hatches: Blue-Winged Olive (BWO), Pale Watery, Caenis, Iron Blue Dun, Midge.

• ​Observations: The "Angler's Curse" (Caenis) appearing in white clouds at dawn/dusk; the distinct three tails of the BWO.

​July & August

​The Dog Days & The Ethical Angler

In recent years, Welsh summers have trended toward the extreme, with long periods of drought and low, crystalline flows. During these "Dog Days," common sense must prevail over the desire to cast. For the true Welsh riverman, fish welfare is the utmost priority.

​When water temperatures reach the 16°C to 19°C  range, again that may be circumstancial, for each river will have its own range depending on densityof bank side trees, flow and topography. Trout struggle to recover from the stress of a fight due to lower oxygen levels. If the thermometer hits these levels, the ethical choice is to stop fishing entirely or wait for the cooler respite of late evening. We protect the resource so it survives for seasons to come.

• ​Tactics: Small flies, long leaders (15ft+), and flawless presentation are non-negotiable. One heavy footfall or a poorly presented fly lineover a pool will end your chances instantly.

​Dry: BWO (blue winged olive)  Black Gnat, Iron blue dun, PMD( Pale Morning Dun) PED (Pale Evening Dun), Elk Hair Caddis, midge pattern.

• ​Wet/Nymph: Small baetis Nymph, bubble back BWO Nymph.

  
  

​September (1st – 30th)

​The Last Hurrah

The trout are hungry, preparing for the winter. Smaller flies and subtle presentations are key.

• ​Key Hatches: Autumn Dun, Small Dark Olive, uprights.

• ​Observations: Large autumn duns skittering on the surface early evening ; a return of the Olives. ​

  
  

• Fly Patterns:

• ​Dry: Pull out your Large Brook dun and MB patterns once more for the Autum Duns. Sedge patterns such as the , F-Fly (Grey or Olive), CDC and Elk, Klinkhammer.

• ​Wet/Nymph: Waterhen Bloa, small CDC bubble wing emerger patterns. Small unweighted Baetis.