An easy-to-understand article about barometric pressure and its impact on your fishing
Barometric pressure is just the weight of the air. It constantly pushes down on everything, like a big hand. It presses down on you, the earth and the surface of the water. Stormy weather results from low pressure, when the hand of the atmosphere pushes down with less strength. On the opposite end of the spectrum is clear blue skies come from high pressure or a heavy hand.
Most people use a barometer simply to help them guess as to whether they should take an umbrella with them. But, barometric pressure readings can also predict whether fish are likely to be biting, or if they will soon be biting or, perhaps, if it’s best to stay home.
Barometric pressure- the weight of the air- decreases as a storm approaches. It’s called low pressure. To understand how it works, imagine the palm of that giant hand as it presses on the water’s surface. Its touch is lighter. The water isn’t as compressed as it was, and fish can move more easily through it. The mood of many fish often changes to what we might call a more ‘active’ mood. They move around more freely and feed.
A storm also brings clouds and wave-creating wind, reducing sunlight penetration. Active fish can move to shallower water. In the case of walleyes, they often rise in the water column. The sonar screen shows them moving up off the bottom. Or, they just move shallower on shoreline-connected and mid-lake structures. Some believe that the absolute best fishing periods often occur when barometric pressure reaches its lowest point, just before the front arrives.
“The old saying, that fish bite best right before the storm,” is true. The best time to head to the lake is when the forecast calls for storms moving into the area. The picture changes when the storm is over. Barometric pressure starts to rise again. The giant hand presses down harder, and the water becomes more compact. High pressure also brings clear, blue skies, and light penetration is often intense for the next several days. Fish feel the increased pressure and become less active. They move tight to cover or deeper, where the sun isn’t so bright. Their mood is lethargic.
With underwater cameras, you can watch fish come up to a bait and not bite it. People don’t understand that, but when air pressure is high, fish become less aggressive. They just come up and look. They may eventually take it, but you have to coax them a little harder.
The effect of the pressure change is most pronounced on the first day after the storm passes. The time of year must also be considered. The impact of a change in barometric pressure is more severe in winter. For one reason, the swing between high and low pressure is more drastic during the cold months. For another, the same high pressure is affecting less water volume when part of it is locked up as ice.
Fish like northern pike may be the least susceptible to changes in barometric pressure; they seem to be aggressive no matter what. But, the perch family, including walleye, are the most impacted by the changes
A barometer isn’t needed to know what’s happening with air pressure. Read the wind instead. Anyone can play amateur weather forecaster, before the (storm) front, wind is out of the south. When it switches to west-northwest, pressure begins to rise.”
The old saying, “Wind from the east, fish bite the least,” has a basis in fact. Wind comes from the east the longer high pressure is in place, and by then, high pressure has taken a real toll on the fish.
Even when conditions are less than ideal, the barometer can help put more fish in the boat if you’re willing to analyze the effect air pressure is having at that moment.
When you get out on a body of water, people do what they normally have done, they’ll head over and stay in a comfort zone. What they haven’t done is check the weather. If you don’t understand what the weather is doing, you’re already behind the eight ball on learning what the fish are going to want that day. Storm coming? Then low pressure is on its way, and faster, aggressive tactics may be best. For walleyes, trolling or casting crank baits at shallow structures may be the keys. Look for schools cruising up off the bottom. Note the changes in depth as time passes.
When fish are aggressive, you can drop anything down there. Using live bait can be very productive when the barometer points to the aggressive end of the scale. When the barometer is moving downward use bottom-bouncers and Red Devil spinners and if you must slow down, use Lindy rigs.
Slow down even more as the grip of high pressure takes hold. Jigs are one tool of choice at this time. Jig a live bait on a rod to attract walleyes and use a dead-stick to get the bites. The approach works either in open water or through the ice. Because walleye and other fish hold tight to cover, slip bobbers are another favorite.
The lesson? You can’t do anything about the weather. But, you can watch the barometer and predict where fish will be, how they’ll behave and what tactics to use. Weather, if you understand it, can help you choose where and how to fish.