Hot, humid weather and tepid water conditions during late July and throughout August are less than comfortable for trout and trout fishermen. Minimal rain and bright sun beating on rivers and streams saps away water, raises water temperature and reduces the oxygen level in the water. Each of these affects cause trout to be lethargic and less likely to feed. In many waterways during the late summer, conditions become so distressing that fish leave normal runs in favor of more agreeable lies.

Much as humans utilize air- conditioned vehicles and rooms, or seek relief from a well-positioned fan, trout flock to water cooled by Mother Nature. Locating these holding pools is crucial to consistent summer fly fishing success. Many anglers experience poor results along favorite runs, figure the hot weather has ruined the fishing and hang the rod up until the next rain shower.

Many fishermen won’t even venture out during August because conditions are just too hot and uncomfortable. Even early mornings and evenings are muggy and close, and insects consider sweaty, slow moving anglers a veritable feast. For those of us who fish despite harsh heat and irritating insects, minimal pressure by other anglers is a blessing. Wear lightweight clothing that covers as much skin as possible, liberally layer exposed skin with repellant and douse your hat with fly spray. Go native and wade in sneakers and jeans rather than heat-trapping canvas, rubber or neoprene waders. Do whatever it takes to get out there, even during mid-day.

Early this week at mid-afternoon on a day that broached 80 degrees a friend and I visited a moderate-size trout stream in central Aroostook. Using a light Cahill, royal Wulff, Henryville special and a mosquito net, we caught and released 51 native brookies in two hours as the sun baked us, and the brook. From one spring hole the size of a Volkswagen bug we finessed 17 hard-fighting speckled beauties between 6 and 11 inches. Hot weather hadn’t sapped their appetite or strength, nor our enthusiasm.

Finding fish

One key opens the door to consistently successfully summer fly fishing – location, location, location.

Every stream has at least a handful of hot weather holding pools that fish flock to, and once pinpointed, these cool-water caches will produce action year after year.

Spots where tiny creeks inlet or cold springs add water to larger rivers and streams are sure bets to attract trout. Dark colored rock ledges often have cold water seeps, sometimes above ground, often under the surface. Use a thermometer to gauge water temps at mid-stream and then directly below each creek and seep. This will help judge in which direction the cold water flows, which is important since trout will fan out and school along the flow lines.

If you don’t have a stream thermometer, use your hand. A 10- to 20-degree change in temperature is easy to discern.

Deep holes comprise a good portion of late summer holding pools. The simplest to locate and fish are pools of slow moving, quiet water with large rocks along the gravel stream bed. Trout will use the rocks and deep, cooler water for comfort and protection. Remember, deep water is relative to the waterway being fished. On a river a holding pool may be 10 feet deep, while on a forest lined brook, a holding run may only be two feet in depth.

Bank undercuts and spots where brush or a tree overhangs the waterway provide shade and protective cover for trout. Both are sure fire hot weather hot spots to float a fly, and often a spot no longer than a sofa will harbor half a dozen fish.

Bends in the brook where brush, roots, stumps and dead trees tend to fetch up offer another great means of shade and cover. These curves tend to be a bit deeper water as well, and I’ve seen 12- and 14-inch brookies come out of a spot not much larger or deeper than the kitchen sink. The trick with such debris-protected holes is to place a fly within reach of the trout without getting caught on the bank, brush or boondoggle of dry-ki (driftwood).

Runs consisting of a moderate speed current bubbling over a rocky bottom for several yards and then subsiding into a table size piece of calm water are also likely to hold trout. I call these runs riffles, a much calmer, slower version of a set of splashy white-peaked rips. Natural current movement funnels food along the riffles and into the tranquil pool below so trout take up feeding stations and wait. Bubbling, rolling riffles provide more oxygenated water as well.

Casting tactics

As important as fly presentation, when fishing schooled trout, is how to attain the best casting position without spooking the quarry. Be aware of the sun’s position and avoid projecting your shadow across the pool. When possible approach from downstream so any dislodged debris and silt doesn’t inundate the laid-up trout and alert them to a foreign presence. No matter which direction you access from; above, below or from the side, lift your feet and move slowly. Kicking rocks, splashing water and clouds of mud are to be avoided.

Select a casting station as far away from the cool water holding site as you can comfortably cast with regular precision. Allow the fly to float down, not splash or slap onto the surface. Fish the edge of the school first, and slowly work inward as trout are caught. If you drag a feisty trout through the middle of the other fish first thing, the rest will scatter or lay low and sulk. After catching half a dozen brookies from one pool, sit on the bank, commune with nature, and rest the spot for 10 or 15 minutes. It’s possible to spend an eventful hour at one site if you alter casting locations, change flies and rest the pool occasionally.

Tempt deep-hole trout with dry flies first, then try fishing a dry fly wet. As the barely submerged dry fly makes a wake along the surface, deep laying fish are often driven to zoom up and strike, out of sheer agitation. Brightly colored wet flies and bottom hugging leech patterns will often work for the simple reason that trout have been seeing only dry flies.

On narrow, brush enshrouded brooks just placing the fly along a bank undercut, under a leaning tree or along the edge of a pile of wood and debris is a challenge. Too far away and the fish ignore it, too close and you’re caught up. Side arm casts, sling shot casts and dapping are all necessary tactics for fly fishing in tight quarters. The only way to perfect each close quarters type of cast is practice and patience.

Don’t ignore cramped 8- to 10-foot wide creek tributaries of larger rivers. Hot weather often drives trout from the main waterway into the cooler confines of these cold spring brooks. It’s amazing the number and size of brookies that will come out of a two-foot deep pothole the size of a car door.

Potent patterns

For spring holes, seeps, and riffles, dry fly color is more important than size. A No. 14 pattern will work most of the time. You can’t go wrong with a gray Slim Jim, mosquito, Henryville special, blue dun, green drake, Adams or Hendrickson. I never venture forth in hot weather without a yellow or orange-bodied grasshopper pattern.

Delving the depths requires black of olive Matukas or Maribou leech patterns. Wet flies that never disappoint include a trout fin, Parmacheene belle, silver doctor, Montreal and royal coachman.

Crucial to locating and spot casting to schooled up trout during hot weather are a good set of polarized sun glasses, slow careful movement and close perusal of the water ahead. Despite the warm conditions the trout are still around, just relocated, and most other anglers are home. It never ceases to amaze me how the better the fishing is, the less I notice the heat and the insects. Try some cool spots for hot trout fishing and see for yourself.

Outdoor feature writer Bill Graves can be reached via e-mail at bgravesoutdoors@ainop.com