As I backed into my driveway the other night, I glanced at the outside temperature reading on the rearview mirror. 81 degrees Fahrenheit. It was 11:45 pm. Yikes.

For trout streams, perhaps the worst part of a heat wave is the high overnight temperatures. When the mercury dips only into the low eighties after dark, the water doesn’t get a chance to release much of the accumulated daytime heat.

If you’ve been in the trout game long enough, you’ve probably already gotten the message about what high temps do for trout fishing. You’ve either read it somewhere, someone told you about it or you caught some lethargic trout and they delivered the message to you first hand. Anything over 69° is really too hot for safely catching and releasing trout. That’s my number, but with a little research you can find it supported through scientific studies. Trout in warmer water may swim away when released, but they don’t always live.

In many parts of the region, the best choice for keeping your rod bent is to target different species. Try picking on some smallmouth bass for a change or read up on the Rocket School of Carpin’, and take on that challenge.

But if you’re a die-hard trout fisherman, you’ve probably learned how to find cold enough water to keep fishing for trout even in the hottest summers. Opportunities for safe trout fishing are available all across the northeast this summer. You just have to look for them.

Calibrate

It’s all about the stream thermometer. Find the right temps, and you can fish with a clear conscience. If you’re going to push the limit up to the 69 degree line, then it’s probably best to calibrate your stream thermometer first. Years ago I had a stream thermometer that seemed to be reading too high. I googled how to calibrate a thermometer, followed the instructions and realized that, in fact, it was reading about five degrees higher than the actual temp. Here’s the Cliffs Notes:

— Fill a glass with ice and add cold water.

— Mix it up.

— Put the stream thermometer in the glass and let it sit for a few minutes.

— The thermometer should read 32°. Calibrate accordingly.

When I follow these steps, the temperature always ends up to be a little over 32°. I trust the number anyway. It’s better for the trout if I have a thermometer that reads a little high than a little low.

Another way to calibrate is to check the stream thermometer against other trusted thermometers. I have a digital meat thermometer. I place my stream thermometer next to it and read the temp. I also place my stream thermometer on top of the thermostat in my house to check the accuracy.

Using a couple of the above methods, I can calibrate my thermometer and trust the on-stream readings.

Couple Tips

Get out at dawn and quit early. Morning water is the coldest that it will be all day. On my waters, summer action usually shuts down around 10:00 am, and it’s usually not much fun to try to force the issue through the sunlight anyway.

Understand basic trends and patterns for your water. What happens to your river after a midday thunderstorm? Some drainage areas hold water, but in others the short and hard rains run quickly through the system.

Some areas of a river are cooler. You’ll find more fish around springs and tributaries. That said, in many big rivers you may find large pods of trout seeking thermal refuge at the mouth of a tributary. In such a case, I don’t fish for them. You’ll have to find your own ethical line.

Wet wading is a very good way to find otherwise undetectable springs. When you walk over an underground spring, it’s cold. You’ll know it.

Night fishing (late) can be a good option if you’re bold enough to face the dark and you don’t require a lot of sleep.

Evening fishing, though, may not be the best option. Anglers often mention waiting until evening to do their summer fishing, but that should come with some caution. I’ve often taken the highest water temperatures of the day just after the sun leaves the sky. Water holds heat for quite a while, and after absorbing the sun all day long, it should come as no surprise that the warmest water is often just before dark.

Play fish quickly. If you’ve worn them out too much, you’ll know it. If you’re catching trout that are listless and sluggish, then the water is too warm and/or you’re playing the fish too long. Trout in such condition likely will not survive after release.

If you take a pic, lift it from the water for only a few seconds at a time. Really — just a few seconds. I keep the fish in my net, in clear moving water while I quickly set up a tripod. My rubber mesh net acts as a live well for the fish. I then lift the trout only for a moment and take the pic. If water isn’t dripping from the fish, it’s time to put it back into the live well (the net). This is why I like a wooden net. The frame floats. In marginal water, it may be best to forget the picture altogether.

A couple weeks ago, I was gearing up in the parking lot for a night fishing trip. Three fishermen climbed the banks just before dusk, and each of them told me the fishing was slow all evening. They looked hot, tired and frustrated. After dark, I biked upstream two miles, and I spent an hour trying (unsuccessfully) to take some long-exposure night shots with the camera. It was 11:00 pm when I finally took the water temp and started fishing. 68 degrees. Just barely cold enough for trout fishing. I have to assume that the frustrated fishermen I met below (two hours earlier, and two miles downstream) were fishing in water over seventy degrees for most of the evening. They may not have taken a temp, they may not have known that it mattered, and they may not have cared if they did.

I think it’s our job to take care of the resource, to understand what a trout can tolerate, and to remember that they don’t always live just because they swim away.

Good luck on the water this summer.

Enjoy the day.
Domenick Swentosky
T R O U T B I T T E N
domenick@troutbitten.com

Photo by Matt Grobe