Humans and other warm-blooded creatures have internal systems to help them adjust to temperatures above or below what feels optimum. Cold-blooded creatures, like fish, don’t have those systems, but they do have “preferred” temperature ranges. When they get too hot or too cold, they move. If the water is too hot, they often just go deeper. Warm water is less dense and therefore floats on top of cold water. If the depths are too cold, fish will head shallower. But what happens in the winter when fish get all the way to the surface and it’s still uncomfortably cold?

Often, there are areas in a lake that are “warmer” than others, and you can bet many of the fish in the lake—both predators and prey fish—will find these warmer water zones. As a fisherman or woman, if you can find these warmer-water areas, you have found a fishing hotspot. Where should you look?

Every lake or river is different, but some things are constant, whether it’s a small pond, lake, stream, major river or big lake. Look for “solar heated” areas where the rays of the sun can heat the water more than others. Remember, the sun doesn’t shine 24/7, so many of these solar hotspots are transient. They may not exist on cloudy days, and though the top few feet of a lake may warm up on a sunny day, that heat may dissipate overnight.

Fishing shallow on a sunny afternoon may produce good results in spring—especially along the north shore of a lake where the sun’s rays can reach the bottom and heat the water, both from the top down and bottom-up. Sun reflecting off shoreline trees and other structures can even warm shallow flats. Don’t expect these same areas to be as good the first thing in the morning, however.

Another likely place to investigate is anywhere a stream or river empties into a lake. Inflowing water during late winter through much of spring is almost always warmer than the lake water. The larger the stream, the more it produces a warm water zone just offshore of the mouth. Bigger rivers flowing into large lakes often produce a warmwater oasis of several hundred acres—big enough that trolling tactics are warranted, with room for multiple boats.

Smaller streams’ mouths may not have as many fish, but they seldom attract as many anglers, either. Jigging, casting or quick trolling are often productive tactics at the mouths of smaller streams. Quick trolling means slimming down the number of lines being used to allow making quick turns, as opposed to wide, sweeping turns needed when trolling with a full array of rods. Quick turns will keep more lures in the hot zone in the long run.

Most sonar units display the surface water temperature these days, so spend the first part of each the trip learning where the warmed-water pool is located. That can change almost daily due to wind, waves and the amount of water leaving the stream— especially on big lakes. In many places, simply noting water color can be a clue since stream outflow is often more turbid than the water in the lake.

That’s usually not the case at places where artificially warmed water is discharged into a lake, however. Power plants, heavy industry and other facilities often pump water from the lake to cool machinery and equipment in their plants. Once the cold lake water flows through the facility and gets warmed, it’s discharged back into the lake. Places with on again/off again cycling of the water can hold fish, at least temporarily during discharge cycles. Facilities that operate continually start pulling in fish in early winter and often provide reliable fishing on into the spring and early summer.

The keys to success of any fishing trip are always a puzzle, but some pieces of the puzzle are more important than others. When the water is cold, finding places with water even a few degrees warmer than most other areas is often the most important piece of the puzzle.

For more insight and tips for fishing throughout the year, check out the articles in every issue of MidWest Outdoors, available by subscribing on our website.