Seasons & Conditions

May Spring Hatches in North Georgia: Caddis, Sulphurs & Mayflies

Daniel Bowman · Updated June 20, 2026 · 13 min read

What hatches in North Georgia in May?

In May, North Georgia trout water sees three overlapping insect groups: caddis, sulphurs, and a mix of larger mayflies (March Browns and Light Cahills) alongside the last of the spring Blue-Winged Olives. Caddis dominate the first half of the month, sulphurs take over the second half and become the defining evening hatch, and the mayflies fill the gaps with sporadic but high-value emergences. This is the one month of the year when a North Georgia trout will reliably eat a dry fly off the surface for hours at a stretch.

Why May and not April or June? Water temperatures cross into the 55-62°F band where aquatic insects emerge in volume, day length stretches the evening feeding window, and the spring runoff has usually cleared by mid-month so fish can see flies on the surface. April has hatches but colder, less stable water; June starts the slide toward terrestrials and low-water summer conditions. May is the sweet spot, which is why it's the single best month in the spring fly fishing in North Georgia calendar.

Here's the catch that trips up first-timers: the hatch you'll fish depends as much on which river you're standing in as on the calendar date. A tailwater like the Toccoa runs its hatches a week or two behind a freestone creek at the same elevation, because the cold dam release suppresses water temperature. The Soque, fed by spring water, runs its own schedule again. The sections below break the month down bug by bug and then water by water.

May hatch chart for North Georgia

The table below is the working version most guides carry in their heads. Sizes are hook sizes; timing is the typical window for the metro-Atlanta-to-Blue-Ridge band of North Georgia, which can shift 7-10 days earlier or later with the year's weather.

A practical way to read this chart: if you're fishing the first week of May on an overcast, drizzly afternoon, you're throwing caddis and BWOs. If you're fishing the last week of May on a warm, still evening, you're sitting on a sulphur hatch waiting for the spinner fall. The middle of the month is where everything overlaps and you carry the whole box.

Caddis — the workhorse of early May

Caddis is the most abundant and most forgiving hatch of the month, which makes it the best bug for a less-experienced angler to fish. The bulk of North Georgia's May caddis are tan and olive Brachycentrus and net-spinning species in the size 14-16 range, and they hatch in the afternoon, often building to a heavy evening flush.

The reason caddis fish so well for beginners is that the insect is sloppy on the water. Unlike a mayfly dun that sits primly on the surface film, a caddis skitters, flutters, and bounces as it emerges and again when the adult returns to lay eggs. That motion means your fly doesn't need a perfect dead-drift to draw a strike — a small twitch or a swing at the end of the drift can actually trigger the eat. A dragging caddis catches fish; a dragging mayfly spooks them.

Three ways to fish the May caddis hatch, in the order you should try them:

1. Dry-dropper. An Elk Hair Caddis size 14 on top with a beadhead caddis pupa or soft-hackle 18 inches below. This covers fish eating emergers subsurface (the majority) and fish eating adults on top. Start here.
2. The skating dry. When you see adults bouncing on the surface and fish slashing at them, cut the dropper and fish the dry alone with a deliberate twitch at the end of each drift. The strike is violent.
3. The downstream swing. Late in the hatch as females dive to lay eggs, a wet caddis or soft-hackle swung down and across imitates the diving adult. This is the most overlooked and most productive technique of the evening.

For the underlying logic on why size and silhouette beat exact color, the matching the hatch breakdown covers how trout actually key on a bug. Hatch Magazine's mayfly identification primer is worth a read for telling caddis from the mayflies you'll also see on the water in May — the wing posture is the giveaway, with caddis holding a tent-shaped wing over the body while mayflies stand theirs upright like a sail.

Sulphurs — the hatch that defines May evenings

The sulphur hatch is the marquee event of the North Georgia May, and it owns the last two hours of daylight from roughly mid-month through early June. Sulphurs (Ephemerella species) are pale yellow mayflies in the size 16-18 range, and they emerge in dense, predictable clouds in the evening, then return as a spinner fall after dark that can carpet the surface.

What makes the sulphur hatch special — and frustrating — is its density. When a few hundred natural duns are drifting through a run, your single artificial is competing against a wall of real food. The fish settle into a steady, rhythmic feeding lane and become genuinely selective. This is the closest North Georgia comes to true Western-style hatch-matching, and it's where a guide earns the trip fee by reading exactly which stage the fish are eating.

The sulphur hatch comes in three fishable stages, and you need a fly for each:

• Emerger / cripple (the most-eaten stage). Fish hold low in the film and pick off duns struggling out of the shuck. A sulphur sparkle dun or a soft-hackle emerger fished in the surface film outproduces a high-floating dun most evenings.
• Dun. Fully emerged adults riding the surface. A size 16 Comparadun or thorax dun in pale yellow. Best during the heaviest part of the emergence.
• Spinner. Spent adults that fall to the water after mating, usually right at and after dark. A rusty spinner size 16-18 fished by feel in the last light is the trophy-fish window — the biggest browns wait for the easy meal of dead, drifting spinners.

The single most common sulphur mistake is leaving the river too early. The hatch peaks as the light fails, and the spinner fall — the best fishing of the day — happens when most anglers have already broken down their rods. The best time of day to fish almost always points back to that last hour in May. Stay until you physically cannot see your fly, then stay ten minutes longer.

March Browns, Light Cahills, and the larger mayflies

Alongside the sulphurs, May produces a rotation of larger mayflies that give the trout a bigger meal and give you a more visible fly to fish. The two that matter most are March Browns (size 12-14, mottled brown, first half of the month) and Light Cahills (size 14-16, cream-yellow, late May into June).

These bigger mayflies don't hatch in the dense clouds that sulphurs do — they come off sporadically, a few at a time, through the afternoon and into the evening. That sparseness is actually an advantage for the angler. Because there aren't hundreds of naturals competing with your fly, a trout that's tuned in to March Browns will move a long way to eat a well-presented size 12. A sparse hatch of large bugs often fishes better than a dense hatch of small ones.

How to play the larger mayflies in May:

• Fish the nymph first. A size 12-14 Hare's Ear or pheasant tail dead-drifted through riffles imitates the active nymphs days before and during the hatch. This is your bread-and-butter subsurface bug all month.
• Watch the riffle heads. March Browns and Cahills emerge from faster water. The trout that eat them sit at the tail-out below a riffle, waiting for the current to deliver duns. Cast to the seams there.
• Go bigger than you think. Anglers conditioned to tiny flies undersize their imitations. A confident size 12 parachute drifted over a fish that's been eating March Browns will get crushed.

Little Yellow Stoneflies (yellow Sallies) overlap this window too, in the same size 14-16 range. A yellow Stimulator does double duty — it reads as both a stonefly and, in a pinch, a large mayfly or skittering caddis. If you can only carry one searching dry in May, a size 14 yellow Stimulator is a defensible choice.

How the hatches differ river by river

The same calendar week fishes differently on each North Georgia water because water temperature — not air temperature — drives emergence. Below is how May breaks down across the rivers a guided trip will put you on.

Toccoa River (tailwater). The cold release from Blue Ridge Dam runs the hatches a week or two behind the freestone creeks. May is prime caddis on the Toccoa, with sulphurs building late in the month. The generation schedule matters more than the hatch chart here — you fish the hatch when the water lets you. The Toccoa River guide covers the generation logistics that govern any Toccoa hatch day.

Soque River (spring-influenced freestone). Stable, cool spring water means the Soque carries a hatch the earliest and most reliably. May sulphurs and caddis overlap with the river's year-round midge and sowbug base, so the trout are well-fed and selective. The technical sight-fishing the Soque is known for rewards a precise hatch match more than any other Bowman water. The best flies for the Soque River breakdown goes pattern by pattern for this water specifically.

Noontootla Creek (high freestone). Pure freestone in the Cohutta high country. May brings sulphurs, Light Cahills, and a richer caddis mix under the hemlock canopy, plus inchworms and beetles dropping from the trees by late month. Small flies, short drifts, and a careful approach matter here — the wild browns are unforgiving of a bad presentation regardless of how perfect the hatch match is.

Etowah and Tuckasegee. The Etowah, the closest trout water to Atlanta, runs a freestone schedule with strong May caddis and the same sulphur build. The Tuckasegee across the line in North Carolina runs a tailwater pattern similar to the Toccoa, with hatches keyed to the generation cycle.

The takeaway: if you're picking a May date and want the highest odds of a dry-fly hatch on the water, the spring-influenced Soque is the most reliable bet, the freestone creeks peak mid-to-late month, and the tailwaters fish the hatch behind the calendar.

A worked example — fishing a May sulphur evening

To make the abstract concrete, here's how a guided May evening on a North Georgia freestone typically unfolds.

You're on the water by 4 PM. The afternoon is warm, the water is clearing from the last rain, and a few caddis are bouncing around. You start with a dry-dropper — a size 14 Elk Hair Caddis trailing a size 16 pheasant tail — and pick up fish on the nymph in the riffles for the first hour. Nothing dramatic, but steady action.

Around 6:30 PM, the light softens and you notice the first pale yellow duns riding the surface in the slower tail-outs. The fish that were holding deep slide up into the film and start showing soft, subtle rises — head and shoulders, no splash. That refusal-to-splash is your tell: they're eating emergers, not adults. You cut the dropper rig and tie on a sulphur sparkle dun in size 16, fishing it dead-drift in the film.

By 7:45 PM, the hatch is at full density. There are too many naturals; your fly is getting refused on every other drift. This is the selective window. You shorten your tippet decisions to one thing — get a clean, drag-free drift in the exact lane the fish is feeding in — and let the size and silhouette do the work. The fish that eats does so because your fly happened to be the one in the lane at the right second, not because it was a better imitation.

At 8:30 PM, the light is nearly gone and the duns thin out. Then the spinner fall starts — spent rusty-bodied mayflies drifting flush in the film. The biggest fish of the evening, a brown that ignored the duns all night, starts feeding in a slow glide. You can barely see your size 16 rusty spinner. You fish by feel and by the sound of the rise, set on the slurp, and land the best fish of the trip in near-total darkness. That is a May sulphur evening, and it's why guides circle this month on the calendar.

What to bring for May hatches

Your May fly box is bigger than any other month because three insect groups overlap. If you're fishing a guided trip, the guide supplies everything dialed for the day — this list is for the self-equipped angler.

Dries:

• Elk Hair Caddis, tan and olive (14-16)
• Sulphur Comparadun / sparkle dun (16-18)
• Rusty spinner (16-18)
• Parachute March Brown (12-14)
• Light Cahill (14-16)
• Yellow Stimulator (14-16)
• Parachute Adams (14-18) as an all-purpose mayfly

Subsurface:

• Beadhead pheasant tail (14-18)
• Hare's Ear nymph (12-16)
• Soft-hackle / caddis pupa (14-16)
• Sulphur soft-hackle emerger (16)

The rest of the kit: 9-foot 5-weight for most water (a 3-weight for Noontootla's small water), 9-foot leaders to 5X with 6X tippet for the selective sulphur evenings, floatant, and a headlamp — because the best fishing happens after you can see. Polarized sunglasses for the daytime caddis fishing. Coldwater conservation groups like Trout Unlimited maintain a lot of the access and habitat these hatches depend on; their local chapter stream reports are worth checking before a self-guided May trip.

Daniel Bowman

Owner & Head Guide · Bowman Fly Fishing

Daniel has guided fly fishing trips in North Georgia for over 20 years. He runs Bowman Fly Fishing with a team of 10 guides on the Toccoa, Soque, Etowah, Noontootla, and Tuckasegee — including private water access most anglers never get to fish.