Under Pressure

Fishing Tip – from the Colorado Division of Wildlife

We are all aware of “Barometric Pressure”, but what is it, and does it have an effect on fishing?

The first barometer was created in 1644 by Evangelista Torricelli, a mathematician, along with help from scientist Galileo Galilei. Since its conception the barometer has undergone many changes in design, and has proven invaluable from predicting the weather, to avionics.

The barometer recognizes changes in atmospheric pressure by measuring the weight of the atmosphere, which surrounds us. The atmosphere exerts pressure on all of us, and on all bodies of water. We know there is a direct correlation between “Barometric Pressure” and how a person may physically feel. Arthritis pain and headaches can be common with a changing barometer. This physical change that may affect some individuals is believed by many to also effect fish and how they feed.

There are as many differing opinions as to the effects of “Barometric Pressure” and fishing as there are anglers. The following information is based on my observations and notes taken on fishing trips for over 20 years. I feel there is a definite connection between Barometric Pressure and fishing success or the lack of. I do believe you can improve success by monitoring barometric pressure and looking for high or low pressure systems, a pressure system that is moving and anticipating trends.

For Colorado, the barometric range for acceptable fishing is 29.80 to 30.20, 30.00 being the center of attention. Let’s break down the phases of barometric pressure.

Stable pressure: When the barometer is not rising or falling. Extended periods when the barometer is just sitting there seems to put fish in some sort of trance. They are not interested in anything. I have tried using everything in my tackle box from lures and flies to crank baits, with little or no results.

High pressure: When the pressure is high, (above 30.15) you can count on sunny days with very few clouds, if any. Fish will hit occasionally but are not as active. You can trigger some species to strike, but for the most part fishing is slow. Fishing off the bottom seems to work best during periods of high pressure.

Low pressure: When the pressure is low (below 29.85) fish are more active. They seem to be more aware of their surroundings and alert but still reluctant to bite.

Falling pressure: This is where things can get a little confusing. A falling barometer may indicate a change in the weather, with wind, rain or snow a possibility. If the pressure has been high (above 30.15) but begins to fall at a constant rate, fishing can really pick up, even though the pressure is still high. I look forward to fishing when the barometer is falling. It is during this time that fish will hit just about anything and everything.

Rising pressure: A rising barometer can affect fishing much the same as a falling barometer. If the pressure has been low (below 29.85) and begins to rise fish become more active. It seems they are more concentrated to a specific area. Once you find where they are, fishing can be very productive.

Moving pressure: When the pressure is moving, the bite is on. You can tell when the pressure is moving by observing your pets or watching your bird feeder. During periods of a moving pressure system, dogs and cats will head for their food bowls, and your bird feeder will be in high demand. A moving system provides the best fishing, so long as it does not move too high or too low.

Fishing Barometers may be purchased at many local Sporting goods shops ranging in price from $12.00 to over $100.00. If you purchase a Barometer/Altimeter combination be sure the altimeter is compatible with Colorado’s higher altitudes.

As a final note: The barometer is a tool that can be of great benefit. But like so many things in life, it is not an absolute. I have fished when the pressure was ideal and couldn’t buy a bite. Other times I have fished when the pressure was what I considered terrible, and I have caught fish. Over all, the barometer has led me in the right direction, the vast majority of times.