Spring Is Here: The 'Match the Hatch' Guide to Wyoming’s Early Season Insects
Let’s be honest: Spring in Wyoming is a bit of a personality test. You’ve got one foot in a snowbank and the other in a drift boat. The wind is doing its usual 40-mph "Welcome to the Cowboy State" whistle, and your fleece liners are working overtime. But for those of us who live for the tug, this is the most underrated time of the year.
While the fair-weather anglers are still sitting by the fireplace dreaming of July grasshoppers, the real magic is happening right now in our tailwaters and spring-fed reaches. The ice is receding, the water temperatures are creeping into that "wake-up call" 40-degree range, and the trout are starting to realize they’re actually quite hungry after a long, lean winter.
But here’s the catch, literally. Early season trout aren’t exactly throwing caution to the wind. They’re selective, they’re concentrated, and they’re keyed in on some of the smallest insects in the kingdom. If you want to bend a rod before the runoff hits, you need to understand the early season "hatch" and how to match it.
Grab a coffee (or something stronger), and let’s dive into the bugs that define Wyoming’s spring.
The Micro-Warriors: Midges (Sizes 18-22)
If you aren’t fishing midges in March, you aren’t fishing. These tiny Diptera are the lifeblood of Wyoming’s winter and early spring fisheries. They are ubiquitous, they are prolific, and they are: frustratingly: tiny.
In rivers like the North Platte (especially Gray Reef) and the Bighorn, midges can hatch in such massive numbers that they form "clumps" on the water that look like floating balls of soot. We call these "Buffalo Midges" because they’re relatively large for their species (maybe a size 18 if you’re lucky), but most of the time, you’re looking at size 20 or 22.
Why they matter: As the water warms just a few degrees, midge larvae become active. Trout will stack up in the slow, deep pools and "sip" the pupae as they rise through the water column. It looks like a tiny bubble or a subtle ring on the surface. If you see that, put down the heavy streamers and pick up the light stuff.
The Strategy:
Nymphing: Run a two-fly rig with a Zebra Midge or a Manhattan Midge. Keep your indicator small; these takes are often subtle.
Dry Fly: If they’re rising, try a Griffith’s Gnat or a tiny Parachute Adams. If you can't see your fly (which, let’s face it, nobody can see a size 22 in a Wyoming chop), tie it as a dropper behind a more visible "sighter" fly.
The Main Event: Blue Winged Olives (BWOs)
If midges are the appetizer, the Blue Winged Olive (BWO) is the first real course of the season. Known to scientists as Baetis, these mayflies are the highlight of April.
There is a legendary rule in Wyoming fly fishing: The worse the weather, the better the BWO hatch. You want those gray, overcast, slightly drizzly (or snowy) days. Why? Because the high humidity makes it harder for the duns’ wings to dry, forcing them to sit on the water longer. This turns the river into a floating buffet line for trout.
Where to find them: The Green River below Fontenelle and the Bighorn are famous for their BWO spectacles. You’ll see them in the slower glides and eddies.
The Strategy:
The "Sparkle" Factor: Use a BWO Sparkle Dun. The deer hair wing helps it float, but the trailing shuck makes it look like a bug struggling to hatch: which is exactly what a lazy trout wants.
Classic Presentation: A size 18 Parachute Adams is the Swiss Army knife of spring. It just works.
If you find yourself struggling to hook up even when the bugs are everywhere, you might be making some rookie moves. Check out our guide on common fishing mistakes to keep your ego in check.
The Big Mac of Spring: Skwalas and Black Winter Stoneflies
Not every spring bug requires a magnifying glass to tie onto your tippet. If you like seeing a "real" bug on the water, you’re looking for the early stoneflies.
Black Winter Stoneflies are small, dark, and often seen crawling across the snow on the banks before they ever hit the water. They’re a sign that the season is officially turning. But the real trophy of the early season is the Skwala.
Skwalas are medium-sized stoneflies (size 10-14) that show up in late March and April. They aren’t as famous as the Salmonfly, but for a trout that hasn’t seen a large meal in months, they are irresistible.
Where to find them: Look for these on the rockier sections of the North Platte or the Green. They love structure.
The Strategy: A Chubby Chernobyl in a smaller size or a dedicated Skwala pattern can produce explosive top-water takes even when the air feels chilly. It’s the first chance of the year to hunt for big fish in the film.
The Secret Menu: Scuds and Sowbugs
Let’s talk tailwaters. Wyoming is blessed with world-class tailwaters like the Bighorn and the North Platte. Because these rivers flow from the bottom of dams (like Seminoe or Boysen), the water stays at a relatively constant temperature. This creates an absolute factory for Scuds (freshwater shrimp) and Sowbugs.
These aren't technically "hatches" because they don't fly, but in the early spring, they are the most consistent food source in the river. When the wind is blowing too hard to fish a dry fly (so, Tuesday), go deep with a sowbug.
Patterns: Ray Charles, Firebead Soft Hackles, or a simple Grey Sowbug.
Pro Tip: If the water is a bit off-color due to early snowmelt, go with a "hot spot" fly: something with a bright orange or pink bead to grab the fish's attention.
Why the Early Season is Special
Beyond the bugs, there’s a biological shift happening. As the days lengthen, the trout’s metabolism begins to ramp up. They move out of the deep, stagnant "winter holes" and start holding in the "seams": the transition zones between fast and slow water.
This is also a critical time for our native species. While we're out there chasing the hatch, remember that some of our friends are preparing to spawn. If you’re participating in the Wyoming Cutt Slam, be extra mindful of where you wade. Avoid the "redds" (bright, clean gravel patches) to ensure the next generation of cutthroats makes it to the net.
Planning Your Spring Trek
If you’re looking to make the most of the 2026 season, there’s more to do than just fish. We’ve got some big things happening in the Wyoming conservation world. If you want to talk bugs, river restoration, and the future of our fisheries with people who care as much as you do, you should definitely join us in Thermopolis for the 2026 Stewardship Conference. It's a great chance to swap fly patterns and help us protect the waters we love.
Final Tips for the Spring Angler
Check the Flows: Spring weather is volatile. A warm day can trigger a "mini-melt" that turns your favorite crystal-clear run into chocolate milk. Check the USGS gauges before you drive three hours.
Watch the Water Temp: Carry a thermometer. If the water hits 42 degrees, the bugs will start moving. If it drops back to 36, head to the truck for a nap.
Dress in Layers: It’s Wyoming. You will experience all four seasons between 9:00 AM and noon.
Clean Your Gear: With the threat of invasive species always looming, make sure you're cleaning, draining, and drying your gear. We want to keep our rivers pristine for the next "Match the Hatch" season.
Spring is a season of renewal, and there’s no better way to renew your spirit than by standing in a cold Wyoming river, watching a size 20 BWO float downstream, and waiting for that golden flash of a trout.
Tight lines, stay warm, and we'll see you on the water!
