By Sean Ward.
It’s important that you check the weather before you go fishing – and not only to know what to wear or whether to bring a raincoat.
You need to know what kind of weather to expect because believe it or not, there is an ideal weather and pressure for fishing.
What is Barometric Pressure?
Barometric pressure, also known as atmospheric pressure or air pressure, is the weight of the air as it presses down upon the earth. You probably don’t feel it, but barometric pressure affects all kinds of things, from the weather to the feeding patterns of animals.
You might think that air is weightless, and to a certain extent, it is. However, gas atoms, water vapor, and other particles all apply light pressure to the surface of the earth. At high altitude, there is less air over you than if you were at sea level – therefore, a high-altitude location has a lower barometric pressure than a location at sea level. Altitude, along with low – and high-pressure systems, can both affect the barometric pressure. There are all kinds of fluctuations that can occur, both during the day as well as during the course of a regular week, month, or year.
Barometric pressure is relatively consistent across the same climate, but there are factors that can influence fluctuations related to local weather patterns, which will create pressure ridges of air that ultimately affect barometric pressure. Barometric pressure is usually affected by the movement of the atmosphere and by temperature, both of which can create high or low pressure.Slight changes in barometric pressure can dramatically impact the behavior of fish. The main reason for this is that everything in water sinks, floats, or suspends midway through the water column. Changes in pressure are similar to changes in gravity, upsetting the ways in which fish move.
How Does Barometric Pressure Affect Fish?
Fish are much more in tune with their environments than we are? They have all kinds of natural pressure-sensing systems, including their lateral lines (sensory organs that are used to detect vibrations and movement in the water). They can pick up on even the slightest changes in barometric pressure. Knowing how barometric pressure can affect fishing is very useful for anglers. Despite the fact that fish live far below the water’s surface, they can still feel the changes in atmospheric pressure. This is mostly due to their organs.
Fish have swim bladders, also known as air bladders. These bladders are inflated sacs that help fish to maintain their buoyancy. As barometric pressure drops, these air bladders inflate to make up for the lowered pressure. As the pressure rises, that bladder shrinks. These swim bladders can become painful for fish as the pressure changes. The fish might have a harder time staying balanced and it will feel bloated, too. To alleviate this discomfort, the fish will try to move around in the water.
Smaller fish may feel this change even more. They will likely head to deep waters when the pressure drops, helping them alleviate their discomfort and to be more balanced in the water.
It’s not just the location of the fish that can change when the barometric pressure rises or falls, either. Their eating habits are also affected. For example, most fish will eat more just before a storm comes in, as well as when it is moving out. You’ll want to monitor the barometric pressure during either of these times, as both can indicate the prime time for fishing.
Some fish won’t be impacted by the barometric pressure and weather quite as much as other species. Smaller fish will be the most affected, but larger fish will eventually feel the difference, too. It might not be that bigger, predatory fish physically feel the air bladder difference – it could just be that as the smaller prey fish head out into deeper waters, the predatory fish feel the inclination to follow them there.
What is a “Normal” Barometric Pressure?
You can often predict the barometric pressure just by looking at what the norms are for a given area. If you live somewhere at high latitude, you are going to have lower barometric pressure. That said, there are also normal ranges for a given area. Baseline pressure is usually about 29-30 inHg. This will depend on the area in which you live – if you’re at elevation, this might not necessarily be normal for you. Keep track of your local weather conditions and patterns to figure out what your baseline is. Otherwise, if 29-30 inHg can be considered normal, you’ll find that the pressure drops as a storm moves in. Your readings could be between 26-29 inHg in this condition. As the storm moves out, the barometric pressure will rise. If the pressure is higher than 30 inHg, you can usually consider it to be a high-pressure day.
Which Barometric Pressure is Good for Fishing?
You’ll likely hear different advice from just about everyone, but for the most part, there is a barometric pressure that’s more optimal than the others for fishing. If you are fishing in conditions of high pressure -30.50+ with clear skies – the fish will bite slowly, usually in deep water or near some cover. You’ll need to use slower fishing techniques since they’ll be more hesitant to bite and act a bit lethargic. In conditions of medium pressure, between 29.70 and 30.40, the weather is fair, and fishing will be more or less normal.
Not great, but not terrible, either. You’ll find that you may need to use a variety of baits and gear to help attract fish. In conditions of low pressure or those with a pressure less than 29.60, the fishing will be slow. The weather is usually cloudy and rainy, and you will need to target fish near cover or in deep water.
As the pressure rises and weather conditions improve, the fish will be a bit more active. Again, you’ll want to go after fish in deep water or near cover. Fish in stable conditions or fair weather will be pretty much normal. Again, the fishing isn’t the best but it’s also not the worst. Now is a good time to try out various new baits or gear.
Finally, in conditions of degrading weather or falling pressure, this is your time to shine. It is in these conditions that you will experience the best fishing, as the fish are likely to take any kind of food you can offer them. Some of the best fishing will occur in conditions of declining or falling pressure, but that’s not to say that it’s the most reliable. If you want to know what to expect – even if it’s not always the best – you’ll be best off fishing in steady pressure.
What Kind of Weather Conditions Are Great for Fishing?
Pressure changes can trigger fish activity, but so too can incoming weather systems. A major cold front, for one, can have a dramatic impact on how fish feed and behave. This usually has more to do with the impacts of the weather change than the weather or the air pressure itself. For instance, when a spring cold front rolls in and cools down water temperature in a shallow bay, the fish will head to deeper water where it’s warmer. You’ll notice that the bites stop completely. It’s all about the timing of cooler weather, though. At the end of summer, when the weather has been hot, a cooler day that drops the surface temperature of the water can cause a feeding frenzy.
Fishing in Good Weather vs Fishing in Poor Weather
When you’re fishing in good weather – what I’ll call a “bluebird day” with sunny skies and calm waters – you are going to want to reconsider your fishing technique. For the most part, you’ll want to fish more in areas of cover and remember that fish aren’t going to be as active. You will want to move slowly and methodically. If you are fishing in low pressure, the fish can usually be found deeper. They won’t be feeding as actively, and you’re also going to have to slow yourself down in order to draw them in.
How to Monitor Pressure for Fishing
You can’t predict the weather, but often, you can predict the fishing conditions by monitoring the barometric pressure. To do this, you may want to invest in a fishing activity monitor. These portable fishing barometers come with temperature sensors and displays. Designed to be used in a wireless setting, this kind of tool will highlight fishing moon phases so that you can keep track of the ideal fishing conditions and predict how fish will behave. Most weather apps will tell you the current barometric pressure and weather along with the predicted conditions. Otherwise, keep track of patterns and norms in your climate and specific location. Knowing what’s normal for where you plan to fish will help give you an idea of whether you are fishing on a high-or low-pressure day – and it will allow you to plan accordingly!