August Fly Fishing: 5 Essential Tips, Techniques, and Flies to Make Your Time on the Water More Productive

Get out early to beat the heat

August can be one of the most rewarding months to fly fish across the United States, but it also presents a few unique challenges.

Summer heat can raise water temperatures, trout may become more cautious, and the best fishing windows often shift to early morning or late evening. At the same time, August brings excellent terrestrial fishing, dependable small-insect activity, and opportunities to catch trout on everything from tiny dry flies to aggressively stripped streamers.

Whether you are fishing a high-country creek, a Western tailwater, a freestone river, or a cool mountain lake, these five August fly fishing tips will help you find more fish and protect the resource along the way.

1. Fish Early and Watch the Water Temperature

During August, the best trout fishing often happens shortly after sunrise.

Cool overnight temperatures help lower the water temperature, increase dissolved

oxygen, and encourage trout to feed. By afternoon, especially on lower-elevation freestone rivers, the water may become too warm for safe catch-and-release fishing.

A stream thermometer should be one of the first things you pack during late summer.

As a general rule, begin exercising additional caution when water temperatures approach 61 - 65 degrees Fahrenheit. When the water reaches approximately 66 degrees, it’s time for a hard stop targeting trout and move to colder water or another species.

Trout may still eat in warmer water, but the stress of being hooked, played and released can significantly reduce their chance of survival.

Several fisheries in the Yellowstone area have recently closed due to high water temperatures.

Early Morning Techniques

Arrive before sunrise and focus on the first several hours of daylight. Start with subsurface flies while the light is low, then watch for rising fish as the morning progresses.

Good places to look include:

·         Shaded banks

·         Deep pools

·         Springs and tributary mouths

·         Fast riffles

·         High-elevation streams

·         Cold tailwaters below dams

Once the water becomes too warm, make the switch to bass, carp, or other warm-water species.

Go To Flies

·         Pat’s Rubber Legs

·         Zebra Midge

·         Pheasant Tail Nymph

·         Perdigon Nymph

·         Small Woolly Bugger

2. Take Advantage of Terrestrial Season

Chubby Chernobyl

August is the prime terrestrial season throughout much of the country.

Grasshoppers, ants, beetles, crickets, and other land-based insects regularly fall into the water. Trout quickly learn to recognize these high-calorie meals, particularly on rivers bordered by grass, brush, trees, and agricultural fields.

Terrestrial fishing can also produce some of the most exciting dry-fly takes of the year. A large trout that has ignored small mayflies may move several feet to crush a well-presented hopper.

Technique

Cast hopper and beetle patterns close to grassy banks, overhanging vegetation, logs, undercut banks, and other areas where natural insects are likely to fall.

Do not always expect an immediate strike. Let the fly drift naturally, and occasionally add a subtle twitch to imitate a struggling insect.

A hopper-dropper rig is especially effective in August. The terrestrial serves as both a dry fly and an indicator, while a small nymph covers the area below the surface.

Adjust the distance between the hopper and the dropper based on water depth. In shallow riffles, 18 to 24 inches may be enough. In deeper runs, increase the dropper distance so the nymph reaches the feeding zone.

Recommended Terrestrial Flies

·         Chubby Chernobyl

·         Foam Grasshopper

·         Morrish Hopper

·         Fat Albert

·         Amy’s Ant

·         Parachute Ant

·         Foam Beetle

For the dropper, try:

·         Spanish Bullet

·         Frenchie

·         Zebra Midge

·         Hare’s Ear

·         Pheasant Tail

3. For Pressured Fisheries Go To Smaller Flies, Lighter Tippet, and Stealthier Presentations

By August, many trout have seen months of fishing pressure. Clear water, lower flows, and bright summer sunlight can make them especially cautious.

A fly that worked easily in spring may suddenly receive repeated refusals.

Downsizing your fly and tippet can make a major difference.

On heavily pressured rivers, changing from a size 14 dry fly to a size 18 or 20 may be enough to turn refusals into confident takes. Dropping from 4X to 5X or 6X tippet can also improve the drift and make the presentation less visible.

Technique

Approach the water carefully. Avoid standing on high banks where your silhouette can be seen, and do not immediately wade into the middle of the river.

Begin by fishing the water closest to you. Trout often hold surprisingly close to the bank, especially where there is shade, structure, or slightly deeper water.

Use longer leaders when fishing dry flies in clear water. A 10- to 12-foot leader can help separate the fly from the thicker fly line and improve presentation.

When nymphing, use the lightest amount of weight that still allows the flies to reach the trout. Excessive weight can create unnatural movement and cause the flies to repeatedly snag the bottom.

Recommended Flies

·         Parachute Adams, sizes 16–22

·         Blue-Winged Olive, sizes 18–22

·         Griffith’s Gnat, sizes 18–24

·         RS2, sizes 18–24

·         WD-40, sizes 18–24

·         Zebra Midge, sizes 18–24

·         Small Perdigon, sizes 16–20

4. Look for Faster, Oxygenated Water

As water temperatures rise, trout frequently move toward areas with stronger current and more dissolved oxygen.

This makes riffles, pocket water, plunge pools, and the heads of deeper runs especially productive during August.

Many anglers overlook fast water because it appears difficult to fish. In reality, broken water helps conceal the angler, gives trout less time to inspect the fly, and often allows you to get closer without spooking fish.

Pocket water can also hold more trout than it appears to. A small area behind a rock may provide the perfect combination of slower current, easy access to food, and nearby oxygenated water.

Technique

Use short, controlled drifts rather than trying to fish an entire run with one long cast.

In pocket water, fish each likely holding spot separately:

1.  Cast to the soft water behind a rock.

2.  Fish the seam along one side.

3.  Fish the seam along the opposite side.

4.  Cover the faster water directly below the obstruction.

Keep as much fly line off the water as possible. This reduces drag and allows your fly to travel naturally through conflicting currents.

Euro-nymphing and tight-line techniques are particularly effective in these conditions because they provide excellent depth control and direct contact with the flies.

Recommended Flies

·         Frenchie

·         Perdigon Nymph

·         Prince Nymph

·         Copper John

·         Pat’s Rubber Legs

·         Hare’s Ear

·         Caddis Larva

·         Walt’s Worm

A versatile 10-foot fly rod can be especially useful for controlling drifts through fast pocket water while still offering enough flexibility for dry flies and dry-dropper rigs.

5. Adjust Your Strategy After Summer Storms

Afternoon thunderstorms are common in many parts of the United States during August. These storms can temporarily cool the water, add color to a river, and wash insects into the current.

The period during or immediately after a storm can produce excellent fishing, provided conditions remain safe.

Cloud cover may encourage larger trout to leave protected holding areas. Slightly stained water can also make trout feel more secure and less suspicious of larger flies.

This is an excellent time to put away the tiny dry flies and try streamers, stonefly nymphs, worms, and other substantial patterns.

Technique

Look for areas where runoff, side channels, or tributaries enter the main river. These locations may carry dislodged insects and other food.

Fish streamers along:

·         Undercut banks

·         Deep pools

·         Logjams

·         Boulder edges

·         Drop-offs

·         Current seams

Experiment with the retrieve. Start with short, quick strips, but also try a slower swing or dead drift. Trout may respond differently depending on the amount of color and current in the water.

Always pay attention to weather conditions. Avoid exposed ridges, open fields, and the water itself when lightning is nearby. Flash flooding can occur quickly in narrow canyons and desert watersheds.

Recommended Flies

·         Woolly Bugger

·         Sculpzilla

·         Sparkle Minnow

·         Mini Dungeon

·         Zonker

·         Pat’s Rubber Legs

·         San Juan Worm

·         Squirmy Worm

Bonus: Pay Attention to August Hatches

August hatches vary considerably across the United States, but several insects are commonly important.

Depending on the river and region, you may encounter:

·         Tricos during the morning

·         Small blue-winged olives

·         Midges

·         Caddis

·         Yellow Sallies

·         Spruce moths

·         Flying ants

·         Grasshoppers and beetles

Trico fishing can be especially productive on tailwaters and spring creeks. These tiny mayflies often create dense morning spinner falls, bringing large numbers of trout to the surface.

Because the natural insects are so small, presentation is usually more important than having a perfect imitation. Focus on creating a drag-free drift and placing the fly directly in the trout’s feeding lane.

Essential August Fly-Fishing Gear

·         A stream thermometer

·         Longer leaders

·         5X and 6X tippet

·         Terrestrial patterns

·         Small mayfly and midge patterns

·         A selection of weighted nymphs

·         A few streamers

·         Floatant and dry-fly desiccant

·         Sun protection

·         Plenty of drinking water

A 9-foot 5-weight remains one of the most versatile choices for general August fishing. It can handle hopper-dropper rigs, small dry flies, nymphs, and moderate-sized streamers.

For small mountain streams, a shorter 2-weight or 3-weight offers better control in tight surroundings. 

Anglers spending most of their time nymphing larger Western rivers may prefer the additional reach of a 10-foot rod. 

Whether it’s a Fryingpan, Gunnison or Conejos rod, we have the rod you need to fit the bill. 

Final Thoughts

Successful August fly fishing requires flexibility.

The same river may call for tiny trico patterns at sunrise, a hopper-dropper rig later in the morning, and a streamer after an afternoon storm. Pay attention to water temperature, insect activity, weather, and the type of water trout are using.

Most importantly, protect the fishery. Carry a thermometer, minimize handling time, keep trout in the water, and stop fishing when conditions become too warm.

With an early start, a thoughtful approach, and the right selection of flies, August can deliver some of the most memorable fly fishing of the entire summer.

At San Juan Rodworks, we build versatile, high-performance fly fishing gear designed to help anglers adapt to changing conditions without sacrificing performance, or value. Explore our collection of rods, reels, fly line and accessories to find the right equipment for your late-summer adventures.