By Zach Lazzari

Hot summer weather often places trout in danger as water temperatures rise above 70-degrees. Many river systems also experience the highest fishing pressure of the year during these summer months. Under these conditions, trout mortality can quickly spike.

Many state agencies will enact hoot owl restrictions to limit fishing to morning hours with cooler water temperatures. Every angler should have a plan to protect resources and prevent trout mortality during the summer. 

Monitor Flows and Temperatures

Keep an eye on flows and temperatures on your local streams and rivers. Watch the snowpack during winter to help understand how the season will unfold in terms of flows. Get your fishing in early and late in the season and plan on taking a break from the main stem rivers during the hottest parts of summer.

July is especially dangerous in the west. If your local fish and wildlife agency does not report on streamflows or enforce hoot owl restrictions, take a thermometer and check the water temperature in the morning, mid-day and afternoon when the heatwave arrives. If water temperatures push past 70-degrees, it’s time to pursue alternative options.

Head to the High Country

The most vulnerable rivers are the main stem drainages that run through the valleys. These rivers are often dewatered for irrigation needs during the hottest periods of the year. When this happens, trout seek refuge in the coldest zones where oxygen is available and they will survive if left alone.

Take this time to explore the high country creeks and lakes that remain cold throughout the entire year. These areas are often only accessible during the summer when they are ice and snow free. Strap on a pair of hiking shoes and load your pack to explore the thousands of lakes and streams filled with trout in remote mountain hideouts.

Seek Cold Waters

A few places remain immune to water temperature increases and they offer great summer opportunities. Tailwater fisheries have stable water temperatures and some remain ice cold even on the hottest days. 

Focus your efforts on tailwater fisheries in the first ten miles directly below the dam. Temperatures can quickly increase as you travel farther away from the dam. Spring creeks also offer stable water temperatures and reliable flows. If you can locate spring fed waters, take advantage during the hot summer months. 

Alternative Species 

While trout suffer in the heat, other species flourish. Warm water species offer incredible and often under-appreciated fly fishing opportunities. 

Start with the local bass and panfish ponds to start then expand into the world of pike and carp. Pike fisheries frequently overlap with trout and the pike are invasive in some places. Target and keep pike for the freezer when the trout need a break. Carp are another great summer species. They are picky, spooky and difficult to catch but when you do hook one, get ready for a serious battle. Sight fishing for carp is a world-class experience on the fly rod.

Zach Lazzari is a fly fishing guide and an outdoor writer based in Montana. Zach has fished and guided in Alaska, Colorado and Patagonia. Zach is also the blogger behind The Busted Oarlock.