I’ve always been a big fan of autumn fly fishing. Those calm, quiet days when I have the river all to myself, feeling the cold bite of the wind as I walk through slow, crystal-clear water, are some of my favorite moments of the entire season. However, with winter on the horizon, I also treat the fall with a particular frenetic desperation as I try to get my last fix of dry fly action before the big freeze.
Autumn dry fly fishing is a fickle mistress. With Old Man Winter soon to rear his frozen head, water temps begin to cool, and bug sightings become few and far between. However, when fall hatches do happen, they usually happen in earnest with every insect in the area frantically trying to lay eggs before it’s too late. This makes certain autumn hatches absolutely magical, as it seems they can bring every trout in the river to the surface to feed.
Blue Wing Olives
While a lot of anglers think of Blue Wing Olives or BWO’s as a spring insect, there is a smaller, yet substantial hatch of the tiny mayflies that occurs in the autumn. Beginning in late September and continuing well into late November and even December in warmer years, autumn BWO’s hatch en masse in small, isolated pockets of the river, causing trout to feed on the surface of the water like hungry piranha.
Typically hatching in the late morning to early afternoon, autumn BWO’s are a slow-water bug. They hatch in sluggish currents and complete dead water where river depths consistently stay between 2 and 6 feet. Pay particular attention to areas with dark bottom mud or weed growth, as these spots will usually have the highest concentration of both bugs and trout rising up to inhale them from the surface of the water.
Generally, the same basic BWO patterns you use in spring will work during autumn hatches. My favorite autumn BWO flies include emerger patterns like Barr’s BWO and The Humpback in size 18 to 20, especially in the late morning and early afternoon. In the late afternoon and evening, I’ll switch up to more dun-style patterns like classic Parachutes and Comparaduns in size 18 and 16, which ride a little higher in the water and draw more attention from trout in low-light situations.
Mahogany Duns
Mahogany Duns are the final substantially sized mayfly to hatch before winter. Generally emerging in the late afternoon and evenings from late September to late October, these dark-brown mayflies hatch in small numbers but are still large enough to make trout pay attention.
Mahogany Dun hatches are long-lasting, with insects emerging and drifting along the surface of the water for hours, offering plenty of time for trout to find and key in on them. The bugs prefer shallow, medium-flowing runs over gravel bottoms that flow into deeper water. Generally, trout feeding on mahogany duns will stage up in the tailouts and back eddies downstream of these shallow spots where the drifting adults on the surface of the water become easy pickings.
As the trout are generally concentrating on adult mahogany duns, I prefer to use larger cripple patterns. Usually, I’ll pair up two flies like Solitudes D&D and Harrop’s Last Chance in sizes 14 and 16 and then make long downstream drifts into the slower-moving water. However, if I see trout feeding on duns in faster flows, I’ll use more high-profile patterns like the classic Parachute Adams or a March Brown in size 14 or even a 12, which ride a little higher and draw more attention in fast water.
Tricos
If I had to choose a hatch that is underutilized by autumn fly anglers, it would be the Trico. The minuscule mayflies hatch from July to Halloween in most places, and while they are often ignored by fish when other, larger insects are hatching, trout will absolutely pig out on Tricos in the late fall. Hatching in massive clouds that can be mistaken for wildfire smoke, autumn Trico hatches can cause good-looking runs to become bubbling cauldrons of feeding trout at the right times and places.
During a Trico hatch, trout will stack up in areas where the insects are the most condensed. Look for back eddies, dead water flats, and tight current seams that act as buffet lines for trout rising to inhale dozens of the tiny insects at a time. Most autumn Trico hatches occur in the early to mid-morning, so it’s best to get on the water early and stake out a likely looking spot. Once you see bugs beginning to emerge and fish starting to rise, get into position but hold off on casting until you see the river really start to boil.
As Tricos are small and hard to see, I prefer to fish larger-than-average patterns paired with small droppers. Typically, my lead fly will be a Trico Parachute or even a Black Gnat in sizes 12 to 16. Then I’ll tie on a small dropper like a CDC Trico or Trico Sparkle Dun in size 18 to 22, offering the fish two options, with the larger lead fly acting as a strike indicator for when trout eat the dropper.
Autumn Caddis
The Autumn Caddis or Small Dot Wing Sedge is a smallish caddisfly that hatches late in the season. Usually emerging in late September, these bugs will hatch all the way to late November, offering great late-season dry fly opportunities. While they can be confused with the more popular October caddis, Autumn Caddis are much smaller, measuring around 1 inch in length, with brown to olive colorations rather than orange or ginger.
Though fish largely ignore them when they first emerge, these late-autumn-hatching insects eventually become an incredibly important food source for trout, as they are almost always the last substantial bug to hatch before winter. Autumn Caddis prefer to hatch in shallow, faster-flowing rivers and streams with a lot of rocks and slow-growing vegetation. Unlike other caddis species, Autumn Caddis are crawlers rather than swimmers and tend to gather along banks with larger rocks and steep drop-offs. Trout really begin to focus in on the insects during late afternoon when the bugs fly back off the rocks to lay eggs in slow pockets and pools around the edges of faster water.
I try to never overcomplicate autumn caddis fishing. I use simple patterns like Elk Hair Caddis, Caddis Variant, and Headlight Caddis in sizes 12, 14, and 16. All these flies can be plunked down, drifted, and skated in the small pockets and pools where hungry autumn trout are on the hunt.
Midges
While midges hatch all year, they’re mostly ignored by trout until water temperatures really begin to drop. Once the real cold sets in from late October to late November and into December, these tiny insects become a big part of a trout’s diet as they transition into winter feeding mode. When a heavy midge hatch is really going on, you can find trout gulping down mouthfuls of micro bugs on the surface of the water, even on the coldest autumn days.
The best dry fly midge action usually happens when the weather is calm and slightly overcast, and air temperatures are in the mid-30s to low-40s. Concentrate your efforts on long sections of smooth-flowing water near tailouts and don’t cast until you spot rising fish. Rises on midges are very subtle, usually little more than a tiny dimple on the surface, so be vigilant and try to find a pod of actively feeding fish that are rising repeatedly before casting.
Just like with Tricos, I prefer to fish a larger midge pattern or cluster pattern paired with a single fly during the autumn. I’ll pair a larger cluster pattern like a Griffiths Gnat or Rio Renegade in size 14 to 16 with a smaller CDC or Para Midge in size 18 to 20 as a dropper.
Last Call
Those last few dry fly days of autumn can be truly special. It’s a time of gentle, slow casts to gentle, slow trout, where rises are barely perceived, and every successful hookset feels like a miracle straight out of heaven. It’s a time of peace and serenity where you calmly walk the river, taking in the kaleidoscope of autumn colors while keeping your eyes on the water as you look for rising trout and one last chance to make it count.