Summer Fly Fishing Bug Guide

The Top Flies and Hatches for Summer Fly Fishing

Summer fly fishing is what everyone dreams of when they want to go fly fishing. Green landscapes and blue skies that mirror the cool and crystal clear waters that trout inhabit. Summer sun warming your skin as you ditch the waders and enjoy the cool temps of the river. Perhaps the best time to connect with nature, summer fly fishing embodies the love and passion we all share for the sport. If that isn’t enough, camping and the wealth of additional activities makes being in the mountains a joy and fills us up in so many ways.

In This Guide

In this guide, we’re going to go through the major differences in the summer season and why they matter for your fly selection and fishing decisions. Then, we’ll go through the major hatches including sizes and colors. Lastly, we’ll wrap it up with the top six flies we recommend for fly fishing in the summer.

Major Differences in Summer Fishing

The Best and Toughest Parts of Summer Fly Fishing


The Best Parts of Summer Fly Fishing

Why is fly fishing so great in summer? There’s the many reasons listed above, but there are a few key reasons I think people have such a love for fly fishing in the summer months. First, it’s the easiest time to catch a fish most days. Trout are at their most active and so are the insects in the river, making it a good chance to find active, feeding trout (something you have to hunt for in the winter months). Having the odds stacked in your favor here never hurts. Secondly, people love warm weather. Instead of 10 below with guides freezing up or torrential rain that is screwing up the rivers, summer has pretty consistent weather in most places trout are found and it’s the best chance to enjoy your day even if the fishing sucks. Lastly, summer fly fishing is great because of the increased access. Winter freezes most rivers except tailwater fisheries, but summer opens up everything from the major rivers to the high mountain streams and everything in between. 

In Colorado, for example, I’ve estimated there are over 850 places to fish (sections and rivers in combination) in the summertime. During the winter there is only around 10 percent of that open to anglers and only a dozen or so that remain consistently good fishing. Summer is the pinnacle of exploration opportunities and for someone like me creating a massive database of Colorado Rivers to fish on the River Explorer, there is nothing more enjoyable than chasing new waters.

The Biggest Challenges of Fly Fishing in Summer

Though summer is full of action, exploration and fair weather opportunities, it comes with some significant challenges as well. The first challenge is the weather. I know I know, I just said how great the weather is, but that heat comes at a cost. Low flows and high temps make for difficult fishing and even dangerous fishing for the trout. If water temps get above 68 degrees Fahrenheit, the fish will begin to struggle to breathe and they will go into a survival mode making them harder to catch. The dog days of summer (mid-July to August) can be slow fishing during the mid-day and the early mornings after the night has cooled the waters is your best chance. It’s important to pay attention to the heat and water temps as it affects your success and the trout’s safety.

The crowds is your next biggest concern. Every Tom, Dick and Harry is out on the river during summer because of all the reasons mentioned above. This means more pressure on the trout and can result in a tougher day on the water in pressured waters. Luckily, with a little bit of effort you can often avoid crowds by either driving further, or hiking a bit to get away. I’ve found 95 percent of the crowds go away after only one mile off the beaten path. It’s not really that tough, but it’s great no one goes very far because it gives you a chance to find uncrowded waters with some effort.

Lastly and likely the most difficult part of summer fly fishing is the wealth of bugs. It’s a full menu for trout during summer. In our entomology course, we cover the 23 insect/stage combos trout eat at any given time. EVERY SINGLE option of those 23 combos are available to trout throughout summer. If that isn’t enough, there are also half a dozen or more different mayfly species that make that number even higher that are available. This means having the ability to master your fly selection is critical.

Don’t worry! This is the primary reason we made this guide. We want you to know the bugs to expect out there on the river before you go so you can be prepared and bring the right flies and learn the right info on how to identify bugs in the river so you can catch the most fish.  

So without any more delay, let’s get into the bug guide portion of this guide to really help you understand the insects. We provide a list for you to work from as well as some suggestions on assortments you can buy from us that help with these hatches. Make sure to check out the flies in those assortments so you can see how the insects mentioned below match the fly patterns in the assortments. Learning this will help you see gaps in your fly box so you can fill them before you get out on the water. Nothing is worse than getting out on the river and being immersed in a massive hatch with rising trout only to find out you don’t have the right imitation for the hatch. Plan ahead and your days will be epic.

The Ultimate Bug Guide for Summer Fly Fishing

Hatches, Insects, Colors and Sizes to Catch More Fish

There is just about every insect and stage combo available to trout during the summer months, so in a way, this is an exhaustive list of insects that trout eat. Use it as a reference to fill in your fly box. Many fly patterns imitate several species of insects and cover multiple stages, so don’t think you’re needing four of every size, color, stage etc. There’s tons of overlap and in our Crafting Your Fly Box Course, we go over fly pattern by pattern of flies to have for summer, and every other season and occasion in detail. It’s a sweet course, and though I’m biased, it really is an excellent resource that will make sure you are never without the right flies on the water.



Midges are always present in the river system, though they are often overlooked by anglers and trout during summer months.  Don’t forget about these guys if nothing is happening on the river, but be aware that when other, larger bugs are active, trout will pass these up during summer for the other bugs.  

Midges are like soup for humans. You can eat soup anytime, but if there’s a steak or burger coming your way, you’re gonna pass on that soup and chow down on some meat. Soup is hard to pass up in winter time when you just want a stable meal. Remember that, midges are like soup.

  • Stages: Nymph, Emerger, Dry
  • Sizes: #14-24
  • Colors: Any Color Imaginable (Black, Olive, Red, Purple are my favorites)
  • Time of Day: Early morning to mid morning and evening to dusk
  • My Favorite Patterns:
    • Nymphs: Zebra Midge, Mercury Midge
    • Emerger: Foamback Emerger Midge, Top Secret Midge, Smokejumper Midge
    • Dries: Smokejumper Midge, Sprouts Midge Emerger, Griffiths Gnat, Renegade



Caddis are seemingly always on the menu for summer trout. All stages, sizes and colors are available to them as continuous hatches create real good success with a standard elk hair caddis. See the stages, sizes and colors to watch for during summer.

  • Stages: Nymph, Emerger, Dry
  • Sizes: #10-18
  • Colors: Orange, Tan, Olive, Black, Yellow
  • Time of Day: All Day, Hatches tend to happen late afternoon to evening in most places
  • Patterns:
    • Caddis Nymphs: Soft Hackle Hares Ear, Hares Ear, Buckskins
    • Caddis Emergers: CDC Caddis Emergers in Olive and Tan and Orange
    • Caddis Dries: Bloom’s Caddis, Elk Hair Caddis, Missing Link Caddis and more


Summer Bug Guide

Always an important part in a trout’s diet where present, scuds will be an option on many tailwaters and spring creeks year round. Look for their importance on days when other hatches aren’t as prevalent or early/late in the day. That’s when I have the most success. 

  • Stages: Nymph
  • Sizes: #12-18
  • Colors: Grey, Pink, Orange, Olive, Two-Tones
  • Time of Day: All day with importance on early morning
  • Patterns:  Beadhead Scuds and Hotspot Scuds

Annelids (Worms)

Even Damselfly nymphs eat annelids!
Even Damselfly nymphs eat annelids!

Always on the menu, these protein-packed insects are always a good option under a dry fly in a dry/dropper set up. Pro Tip—look for periods after rain, or when water has muddied some or recently risen, annelids get flushed out easily during these periods and are the only time trout seem to prioritize them. Trout will always eat them, but these times mentioned above are of extra importance.

  • Stages: Nymph
  • Sizes: #8-16
  • Colors: Reds, Pinks, Browns, Tans, Purples
  • Time of Day: All day, Anytime… Even at Night (hint)
  • Patterns: Beadhead San Juan Worm (Red is my favorite), Squirmy Worms (pink FTW)



Streamers are always on the menu. Look to fish them early in the morning or late in the evening and into night for best results. I find anytime you can fish a streamer where there is transition is best. Transitions from light to dark, deep to shallow, fast to slow, muddy to clear and so on all create places of opportunistic takes from trout, and streamers do well in that scenario. 

  • Sizes: #2 – #14
  • Colors: Black, Olive, Brown, Red, White, Yellow
  • Patterns: Wooly Buggers, Egg Sucking Leeches, Autumn Splendors, and conehead muddy buddies and squirrel zonkers do great, but many streamers patterns will produce so find some you like and can afford and enjoy!



Summer is a cornucopia of mayfly opportunities. Baetis (BWO), PMD, PED, Pseudos, green drakes, hex, cahills, Isos and the list goes on. You don’t always need to know what species is hatching as much as you just need to match the size and color, but understand there is a wide variety that can be hatching at any time. Mayflies really screw up the simplicity of fly fishing, especially in summer and will be your biggest challenge. We have a general list below, but we cover this in full detail on our Entomology course you can check out here.

  • Stages: Nymph, Emerger, Dry, Spinner
  • Sizes: #6 – #24
  • Colors: Grey, Olive, Brown, Black, Purple, Yellow, Cream and More
  • Time of Day: All times of day (depends on species)

Common Species List:

  • Baetis (BWO)
    • Color: Olive
    • Sizes: #14 – #24
  • Callibaetis
    • Color: Tan/Grey
    • Sizes: #14 – 18
  • Pale Morning Duns (PMD) (Sulphurs)
    • Color: Tan, Cream, Yellow
    • Sizes: #14- 18
  • Tricos
    • Colors: Black, White
    • Sizes: #18 – #26
  • Hex Mayflies
    • Colors: Yellow
    • Sizes: #8 – #14
  • Isonychia (Iso) (Slate Drakes, Mahogany Duns)
    • Colors: Brown, Mahogany, Grey, Red
    • Sizes: #12 – #16
  • Green Drakes (Eastern and Western)
    • Colors: Olive, Green
    • Sizes: #8 – #16
  • March Browns
    • Colors: Brown
    • Sizes: #10 – #18
  • Cahills
    • Colors: Cream, Tan, White
    • Sizes: #12 – #18
  • Hendricksons
    • Colors: Brown, Light Brown
    • Sizes: #10 – #18


Summer Bug Guide

Stonefly nymphs and adult dry flies are going to be a staple for trout. There are times of major hatches during the summer months, but there are also sporadic hatches happening throughout summer months so it’s never a bad idea to try one of these during these months. As you’re beginning to see, it’s easy to say EVERYTHING is on the menu in summer, because it really is. This is why it can be hard to know what to use and good entomology and fly selection strategy can really go a long way for your success.

  • Stages: Nymph, Dry
  • Sizes: #8 – #16
  • Colors: Black, Dark Brown, Orange, Red, Yellow, Green
  • Time of Day: All Day 
  • Patterns:
    • Nymphs: Pats Rubberleg, Euro Jumbo Copper John
    • Dries: Stimulators and Rubberleg Stimulators are tough to beat


fly fishing entomology course

Like scuds, sowbugs have a year round importance where present and on days where trout don’t seem to be eating the normal bugs, a sowbug can bring in a lot of fish and is often the missing ingredient for anglers as they are often forgotten.

  • Stages: Nymph
  • Sizes: #12-18
  • Colors: Greys, Pinks, Oranges, Olives, Blues, Whites, Two-Tones
  • Time of Day: All day with importance on early morning
  • Patterns: Ray Charles or Hot Head Sowbugs

Hoppers | Ants | Beetles

Summer Bug Guide

Ants and Beetles show up first in early summer and when it starts to get stable and hot, the hoppers come in full force. Pay attention as you walk along the banks and to and from the river for any terrestrials. Listen and look with your eyes and ears and you’ll know when it’s time to throw these fellas. Pro Tip—windy days are tough fishing, but can make terrestrial fishing excellent. Terrestrial insects don’t purposefully go in the water, they get blown in or fall in, so days when this is more likely will create better hopper and terrestrial fishing.

  • Stages: Dry Only
  • Sizes: #8 – #16
  • Colors: Tan, Olive, Black, Red, Yellow, Purple and any other color you want really
  • Time of Day: All Day, Mid Day seems to be best for hoppers (hottest part of day)
  • Patterns to Use:
    • Hoppers: Parachute Hopper, Hopper Juans, Charlie Boy Hopper, Daves Hoppers (#6 – #14)
    • Ants: Parachute Ants in black and red (#14 – 18)
    • Beetles: Parachute beetle in purple, red and black (#12 – 16)

The Top 6 Patterns for Summer Fly Fishing

The Best Flies for Your Summer Fly Box

The Flies in our Summer Assortment

They Are Also Our Top 6 Flies, Sizes and Colors We Recommend

Coincidence? Nope, we built this assortment based on the knowledge and success we have year after year in the Summer months and put it into a simple and affordable fly assortment that ships in 5-7 days (Free Shipping too!)

Normally $119 | Now $69 ($50 Off)

Coupon Code: SUMMER50

Only While Supplies Last

  • winter-fly-fishing-resources

    Winter Assortment


    Add to cart


    FREE Shipping On All Orders
    • Top producing fly patterns for winter
    • 72 flies | 6 patterns | 3 sizes of each pattern
    • Stock up, or share with a friend
    • FREE shipping, 5-7 day delivery

Flies in the Summer Assortment

Sizes | Colors | Quantities

Zebra Copper John

Zebra Copper John

Color: Black/Silver | Sizes: #12 – #14 – #16
4 of Each Size | 12 Flies Total
Category: Stonefly/Mayfly | Stage: Nymph
Located in Box #7

Beadhead Pheasant Tail

Beadhead Pheasant Tail

Color: Natural | Sizes: #14 – #16 – #18
4 of Each Size | 12 Flies Total
Category: Mayfly | Stage: Nymph
Located in Box #8

BH Rubberleg Prince

BH Rubberleg Prince

Color: Peacock | Sizes: #12 – #14 – #16
4 of Each Size | 12 Flies Total
Category: Stonefly | Stage: Nymph
Located in Box #9

Parachute Adams

Parachute Adams

Color: Gray | Sizes: #14 – #16 – #18
4 of Each Size | 12 Flies Total
Category: Mayfly | Stage: Dry
Located in Box #10

Goddard Caddis

Goddard Caddis

Color: Tan | Sizes: #14 – #16 – #18
4 of Each Size | 12 Flies Total
Category: Caddis | Stage: Dry
Located in Box #11

Improved Sofa Pillow

Improved Sofa Pillow

Color: Orange | Sizes: #8 – #10 – #12
4 of Each Size | 12 Flies Total
Category: Stonefly | Stage: Dry
Located in Box #12