How to Fly Fish for Trout in the Dog-Days Heat of Summer

The the gear and know-how you need for successful catch-and-release trout fishing in late summer

When I think about summer trout fishing, I think about evening sulphur and white fly hatches so thick you can hardly breathe. If you’re a fan of dry fly fishing, the summer is arguably the most action-packed time of year. But the summer is not a great time to be a trout. Trout thrive in cold water, and months of unrelenting sun and low water levels make it difficult for them to stay healthy. Add the stress of a fish fight, and trout can have a tough time surviving the ordeal. Unless you’re specifically fishing for dinner, there are probably less delicate fish than trout to be targeting during the summer. 

However, when the conditions are right and when precautions are taken, you can still scratch the trout itch even in the summer months. But before we worry about how to catch summer trout, let’s take a moment to consider if we should, and when we can get away with it. 

When to Fish for Summer Trout

When water temperatures are in the 45- to 65-degree range, trout are generally pretty happy. Assuming you’re mindful with your handling and release, you can fish without worrying too much about hurting them. But as temperatures rise, the supply of dissolved oxygen in the water diminishes. As water temperatures approach 65 degrees, trout start to have a much harder time recovering. Once temperatures rise above 67, fish become sluggish and may not be able to survive if caught and released.

Fly angler shoots a fly at a trout.
Easily-spooked trout can require a stealthy approach in summer. Cosmo Genova

To avoid unnecessary mortality, a stream thermometer is a must-have tool if you plan to catch and release fish during the summer. This tool will let you know whether the water temperature is in an acceptable range for safe trout fishing. 

Even if water temps are favorable, there are additional precautions you can take when planning a day on the water. It’s generally best to stick to early mornings and evenings on cooler, overcast days when the heat is less oppressive. In terms of locations, look for spring-fed streams at higher elevations, with lots of shade, plenty of moving water, and some deeper pools. Larger tailwaters located below reservoirs with regular cold-water releases are also good places to focus your fishing. Use weather apps and online resources such as USGS Water Data for the current and predicted conditions, water levels, and more when planning a day of fishing. 

If the water is too warm, just go do something else. There are plenty of warm water species, like bass, bluegill, or catfish to target and other outdoor activities to keep you occupied. Of course, if you plan to keep some trout for the table, these guidelines aren’t all that relevant. However, limiting your fishing to areas with abundantly stocked trout will give wild reproducing populations a fighting chance of making it through the summer heat. 

How to Fish for Summer Trout

Let’s say you’ve taken the necessary precautions, found a great location, and the conditions are favorable enough for a day on the water. 

For me, the summer is all about dry fly-fishing. Floating a fly past a happily feeding trout is the epitome of what makes fly fishing different and special, and the summer can be the best time to do it. No matter where you fish, the main food source for trout will be one of several families of aquatic insects, mainly mayflies, stoneflies, and caddis. But the summer also adds terrestrial insects to the menu such as ants, grasshoppers, and beetles, as well as a higher emphasis on gnats and midges. Beyond the famous and prolific summer hatches such as the western salmonfly hatch (a species of stonefly) and the eastern Green Drake hatch (a species of mayfly), what’s prevalent and the progression of seasonal hatches will be determined by location, weather, and timing. 

Fly angler changes flies on the stream.
Summer can be the best season for dry-fly fishing. Bring an assortment of dries to the river. Cosmo Genova

When you arrive at your fishing location, look for bugs in the air, on the water, and under rocks and on stream-side vegetation for an idea of what the fish are feeding on. It’s good to have a variety of patterns in different sizes and colors for you to experiment with, but there really isn’t a substitute for stopping into a local fly shop for some insider info on the bugs du jour

Taking the time to figure out what bugs are hatching, what stage of the bug’s life cycle the fish are keying in on, where and how the fish are feeding, etc., will greatly increase your success and prevent you from needlessly spooking fish you could have otherwise caught. When it comes to fly fishing, especially during the summer, it’s better to cast less, and observe more.

While matching the size and color of the local bugs is a piece of the puzzle, achieving a proper drag-free drift is the single most important aspect of dry-fly fishing. The idea is to lay the line down gently and allow the fly to float past the trout without any unnatural movement or drag on the water. Learning how to mend and move the line without disturbing the leader or the fly will ultimately determine how believable your presentation is to the trout, as well as how well you’ll be able to set the hook and manage your line if the trout decides to eat. 

For the majority of situations, your standard 9-foot 5-weight rod, or something close to that, is the summer do-it-all rod setup. Rods with a slower, softer action are often preferred for delicate dry fly fishing, but use any rod that suits your casting style and gives you the most feeling of control. Any of your favorite weight-forward floating lines will do the trick, but I prefer a line with a slightly longer, more gradual front taper such as the RIO Technical Trout. A longer front taper offers more control when mending, roll casting, or water loading due to the weight being more evenly distributed over a longer section of line. The thinner, lighter terminal end also offers a softer landing when you’re trying to delicately plop a fly in front of a picky trout. 

The low water levels and bright sun of the summer make fish exceedingly spooky, so longer, thinner leaders, smaller flies, and soft presentations are often necessary. A 9 to 12 foot monofilament leader tapered down to a 5 or 6x tippet is usually your best bet. However, a short section of fluorocarbon tippet at the end of the leader can help sink a fly just below the surface when fishing emerger or cripple patterns. 

Yeti Panga backpack on a fishing trip.
A good waterproof pack is essential to keep your gear dry from unexpected summer storms. Cosmo Genova

While it might not directly help you catch more trout, it’s a good idea to be prepared for everything that the summer can throw at you. The sun can cook you alive, even on overcast days, so bring sunscreen or lightweight clothing that can fully cover your exposed skin. And don’t forget to bring plenty of water and stay hydrated. 

Hot summer air in the atmosphere can also lead to weather instability, and violent summer storms are common in many parts of the country. Always check the weather and plan accordingly. In addition to a rain jacket, I always bring a waterproof backpack, a roll top dry bag, and a few Ziplock and trash bags to protect my stuff if I get caught in an unexpected shower.  

While trout struggle in the summer, there are times when you can target them with a clear conscience. Plan around cooler days and places, and always bring a stream thermometer. If the conditions suck, have the self control to call it quits and do something else, or limit yourself to catching stockies for the table. If you’re mindful and prepared, you can enjoy a little summer dry fly action without unnecessary harm to the fish or the fishery.