Hatch Updates: What to Expect for September and October (Western US)

Parachute Mahogany Fall is a great time to be fishing anywhere! Whether it is bass, trout, steelhead, pike or salmon, the opportunities...

Parachute Mahogany

Fall is a great time to be fishing anywhere! Whether it is bass, trout, steelhead, pike or salmon, the opportunities are fantastic and the fish are usually happy.

If you are chasing trout in the west, here are some hatches to prepare for. We want you to be on top of it when the time comes.

Parachute Adams

The big hatch is the Mahogany Dun mayfly. This dark brown beauty can range from a #12 on the big side to a #18 on the smaller end, but a #14 or #16 is by far the most common. Depending on elevation/climate/weather/water temps, the hatch usually starts in early September and rolls steadily into October, peaking out around mid-month.

Our favorite nymph for the Mahogany hatch is the classic Beadhead Flashback Pheasant Tail (we like the curved hook version), but a wide variety of darker colored mayfly nymphs will work in a pinch. A Beadhead Brassie has been productive for me during September, as well a Hare and Copper.

Dave's Hopper

Fall mayflies don't always hatch in that dark brown color. I have seen mayflies hatching in a more burnt orange color, as well as in a more tan than brown color. Another mayfly that hatches in the fall is similar is the Speckled Wing Quill. That is a gray Callibaetis for most of us. A Parachute Adams does the trick on that one, while a Purple Haze, Parachute Mahogany or a Parachute Pheasant Tail are our favorite dries for the Mahogany hatch.

You may also run into some Pale Evening Duns. While nowhere near as prevalent as their earlier-rising cousins, the Pale Morning Duns, these yellow mayflies hatch right as the sun is going off the water. It is not a major hatch in most rivers, but having some pale yellow mayflies is necessary if you are really getting after it. Seeing PMDs is not out of the question during September or October, but the hatch usually starts to wane in the western US by September. Again, that is not a rule, but a guideline. There is always a chance to run into a good PMD hatch anytime that the weather is warm.

Parachute PMD in pale yellow, as well as the Parachute PED are both fine choices in a #14-18.

Ants are great fall trout food

We will still have some good hopper action in much of the west through September and into October. Hoppers stay out until it either starts raining (like real rain), or the temps start to dip below freezing at night. Hoppers are usually smaller in the fall, and seem to be more drab in color, but that doesn't mean the bright ones won't work.

Our favorite is the Parachute Hopper, but Morrish Hopper and Dave's Hopper are popular and effective.

Speaking of terrestrials; Ants and beetles are more active and become a bigger part of a trout's diet in the fall. The Black Ant is great, as well as the Parachute Ant, Foam Beetle Hi-Vis and Suspended Beetle.

Autumn Caddis

Caddis are usually still thick as soup all the way into October. Sizes and colors vary widely from river to river, with several hatching at the same time, but I like to go with a gray #16 for most of my September caddis action. By October however, we start to see the bigger October Caddis. Orange and increasingly large, these badboys can reach up to a size #6 in places and almost rival a salmonfly in caloric intake for a trout. More commonly, they are a #10, but they are not to be overlooked.

The Killa Caddis and the BH Caddis Emerger are great caddis nymphs. For dry flies, the Elk Hair Caddis is hard to beat, but Cutter Caddis, E/C Caddis, and the X-Caddis do the trick for the duller colored caddis, while the Autumn Caddis and October Caddis are your bugs for the bigger orange ones that hatch later on.

Moving through October, we should start to see Blue Wing Olives hatching again. In many places, these bugs only hatch when one or more of the following conditions are met: 1) it freezes overnight. 2) it is dark and cloudy or 3) it rains. This is not always the case, but if the weather starts to turn, expect to see some BWOs.

BWO Quill Body

There are tons of great BWO patterns, but we like Barr's BWO, BWO Quill Body and the Parachute BWO Quill more than most of the others.

There are also some real small bugs hatching as well. Tricos continue as long as it is warm out and midges hatch all the time. Hopefully you won't need to get that small.

One last thing to consider: Fish are trying to pack on weight before winter. I love fishing general attractor patterns this time of year. A big stimulator or a prince nymph often work just as well as the most realistic, hatch-specific fly in the box. So don't be afraid to use that big ugly thing that hasn't got much love lately.

Thanks for reading and good luck with your fall fishing!