While anglers often rejoice when summertime rolls around thanks to warmer weather, dissipating runoff, and spectacular dry fly fishing, it’s important to be mindful of our fishy friends. When the air temperatures consistently climb, the water temperatures will soon follow. Due to extended heatwaves across the country, many of our favorite trout streams and rivers are reaching dangerous temperatures for the very fish we target.
There have been voluntary river closures throughout the country however it’s important that we do our part by fishing at the right times and in the right places regardless of wildlife commission mandates. Knowing when to give trout a break is important and so is maximizing time on the water. These tips will help minimize the impact you leave as an angler.
What Water Temperatures are Safe for Trout?
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67 Degrees Fahrenheit & Above
Fishing for trout in water over 67 degrees is downright discouraged as your catch will unlikely be able to survive the fight to the net regardless of how quickly you land it.
65-66 Degrees Fahrenheit
A few more casts and it’s probably time to head home. Playing fishing in water with temperatures between 65-67 degrees Fahrenheit poses an increased risk to fish and is discouraged.
65 Degrees Fahrenheit and Below
Prime trout feeding water temperatures are between 45 and 65 degrees Fahrenheit. Any warmer and you run the risk of playing a fish to exhaustion. Any colder and those trout will become lock-jawed as they do their best to conserve energy. These are guidelines, however, playing with the warmer end of the spectrum can have dire consequences for the trout on your line.
What can you do when water temperatures rise?
You may be wondering what you can do to stay on the water while being mindful of the potential risks for trout. Like many of our readers, I find it hard to put my gear away during the peak of the season and will share some helpful tips that have kept me on the water.
Tip #1 Use a Thermometer:

Having a stream thermometer will help ensure that you don’t fish in water that’s above 67 degrees. The Fishpond Swift Current Thermometer is a durable choice and can be attached to your favorite zinger.
Stream thermometers can also be used year-round to help find prime feeding water and help time various hatches.
Tip #2 Land Fish Quickly

Landing fish quickly is a good practice in general but is extra important when water temperatures rise. Getting fish to the net quickly will help reduce the amount of stress they go through. Over-playing a fish in warm water is a surefire way to kill a trout. To help land fish quicker, go up a size in tippet i.e. use 3x or 4x when you’d normally use 5x. For dry fly fishing, I prefer to use the Scientific Anglers Absolute Trout Stealth Tippet. When I go subsurface fluorocarbon is a necessity, so the Scientific Anglers Absolute Fluorocarbon Trout Tippet is preferred. Sizing down on tippet may slightly reduce the number of takes you get, but it will help ensure you can land fish quickly and send them back on their way.
Having a longer handle net can also assist in landing and releasing fish quickly and safely. The Fishpond Mid-Length Net is a great all-around option for anglers.
Tip #3 Fish Early
Most anglers are used to early mornings, however, it’s extra important to start extra early during hot summer months to maximize your time on the water. Getting off the water before the peak heat of the day can help reduce the stress that angling places on a fish. When there’s a risk of high water temperatures, I make sure to get off the water around 12pm. This also leaves plenty of time for other summer activities.
Tip #4 Find Cold Water

Alpine lakes and backcountry streams will almost always stay in the safe zone (below 65 degrees Fahrenheit water temps) throughout the summer thanks to being fed by the last melting snowpack. Not only will this help ensure you don’t kill trout from exhaustion, but you’ll be guaranteed to take in some amazing views along the way. Check out our Backcountry Fly Fishing Gear Guide for more helpful tips.
Tip #5 Find New Fish

Summer is a prime opportunity to chase warm water species like bass, carp, and a variety of sunfish like bluegill and crappie. These fish are all a blast to pursue on the fly. These species present new challenges and allow you to vary your tactics. Best of all, many of them can be found just about anywhere in the country. With a little bit of research, you’re likely to find great fishing close to home. Throwing poppers to eager pond fish is a great way to pass any warm summer day.
Tip #6 Give ‘Em a Break

All in all, it’s pretty simple. If the water temperatures are over 65 degrees Fahrenheit it’s best to pack up your trout gear to hit the high country, pursue other species, or take an opportunity to enjoy other past times.
Check available river reports, consult your local fly shop, and take the water temperature with a thermometer if there’s ever a doubt about water temperatures being too high. Sure, we all love to catch trout year-round but sometimes we need to do our part and give the trout a break.
Article by Evan Garda, he is on the Content Team here at Fly Lords. He can be found chasing trout throughout the west with his trusty fly rod. Check out his adventures at @evangarda.
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