Best Barometric Pressure for Trout Fishing

Last Updated on October 2, 2023 by Kyle Whitley

best barometric pressure for trout fishng

When fishing, you want to catch as many fish as possible with the least amount of effort. This is especially true when you’re trying to land a big trophy trout. But how do you find the best barometric pressure for trout fishing?  

In order to maximize your chances of landing a trophy trout, you need to understand how barometric pressure affects trout behavior.   In this article, I’ll explain why barometric pressure matters and how to determine the ideal barometric pressure for your next trip to the river.

What is the Best Barometric Pressure for Trout

Trout prefer low barometric pressure because it means there are fewer clouds in the sky. Clear skies allow them to see more fish and insects.

Trout are cold-blooded fish. They need water temperatures around 55 degrees Fahrenheit (13 degrees Celsius) to thrive.

During low barometric pressure, the air temperature is also lower, but the water temperature stays about the same.

You can still catch trout when the barometer drops, but you might have to go out fishing later in the day. 

Barometer Fishing

Barometric Pressure is the amount of force exerted by the atmosphere on a body when it is at rest. A barometer measures atmospheric pressure by measuring the height of liquid mercury inside a tube.

Liquid mercury is heavier than air, and therefore rises up the tube as the air pressure increases. When the air pressure decreases, the mercury falls down the tube.  

A barometer measures atmospheric pressure by measuring how much mercury is inside a container. A mercury barometer reads 30 inches when there is an air pressure of about one atmosphere.   A strong high pressure can read up to 30.7 inches. Low pressure can read down to 27.3 inches.

Weather systems usually bring storms, hurricanes, tornadoes, etc. High pressure brings sunny days and calm seas.  

All this is really interesting, of course, and how does barometric pressure affect fish?   There are no definitive answers to how a rising or dropping barometer affects fish behavior.  

There is no conclusive evidence that barometric changes affect fish behavior, but fish may be more active when the air pressure drops and less active when the air pressure rises.  

Their bodies regulate their internal environment by changing the amount of oxygen in their blood. Fish have gills that allow them to take in oxygen and expel carbon dioxide.   When the pressure changes, the fish can either move down into deeper water or absorb additional gases through their gills.  

High pressure brings good weather. Fish eat when high pressure comes. Cold fronts come and the fish stop eating.   High pressure brings warm water temperatures and a strong current. Low pressure brings colder water temperatures and a weak current.  

Does barometric pressure affect trout fishing?

Like most fish, trout prefer high barometric pressure (which is often associated with good conditions). When low pressure comes around, their body tissue expands and some organs, like the bladder, swell.

When this happens, fish are known to stop eating and head to deeper water to feel better.

Do Barometric Pressures Affect Humans?

Barometric pressure affects how we feel. Sometimes when the weather changes, our body feels heavy or light. Our blood gets thicker or thinner depending on the weather.

Pressure also affects our bones and muscles. People who suffer from joint pain may experience more pain during periods of low pressure.

Changes in barometric pressure cause blood pressure to rise or fall. Older, more sensitive people can suffer from severe health issues when they experience this type of change. 

fly fishing reeling in a trout
Fly-fisherman catching brown trout in river

Does Barometric Pressure Affect Fish?

Fish have air bladders that help them stay afloat and move around. Fish have an internal organ called swim bladder that helps them regulate where they float in the water column.

Changes in barometric pressure affect the size of the swim bladder. When the pressure rises, the bladder inflates and when the pressure falls, the bladder deflates.

This affects the fish’s swimming ability. A drop in pressure makes the fish swim deeper in search of relief.

Why do trout not like low pressure?

Trout can get uncomfortable when heavy rainfall or snowfall comes around. They’ll swim away from the shallower water, which uses the increased water pressure to dampen the air pressure.

Trout, however, will feed when the water pressure drops. You might be able to get lucky if you’re able to time it right.

When the bad weather passes, the trout will be sluggish coming out of the deep water. If you’re fishing at this point, remember that slow lures or bait may be better than fast ones.

If the weather has gotten better, you can use a variety of different types of lures and baited hooks and probably find them biting again.

How barometric pressure is measured

Barometric pressure is usually measured in atmospheres (atm) or hectopascals (hPa). One atmosphere is equal to the air pressure at the surface of the earth at sea level with a temp of 59°F (15°C).

You can use a barometer to measure atmospheric pressure. A fishing barometer can help you monitor the weather so you know when to go out and fish.

What is considered low pressure?

At 29.60 atm, atmospheric pressure becomes low. During a hurricane, barometric pressure can reach levels as low as 27.30.

Before the storm hits, the air pressure drops. Even if you’re still fishing ahead of the storm when the trout are already headed for deeper waters, they’re probably already there.

What is considered high pressure?

A high barometric pressure reading is listed as 30.5 atm or above. Oftentimes, this high-pressure system develops in clear skies and good conditions. Trout are most comfortable when the water temperature is not hot but also not too cold.

Trout move from deeper waters to shallower ones at high pressures to seek out food. Trout usually bite slowly in this weather, but they may become very active if conditions are near perfect.

Which bait and lures work best for trout during low barometric pressure?

Bait that moves less than normal might be better when there’s low air pressure. Trout love bright-colored baits, but if you’re using them, make sure they don’t move too fast.

Try garlic corn, nightcrawlers, and grasshoppers.  Salmon eggs or doughballs might work as well.

What is the best weather for trout fishing?

Trout fishing is best during warm sunny days when the water temperature is from 34-67ºF (2-19ºC). Trout will usually retreat to deeper water when the weather gets hot, but they can still be caught if you’re using lures and baits that are deep enough.

Should I stay at home?

There is almost always something going on. The only difference is if it’s a banner day. If we become too obsessed with the things we’re going to take all the fun out of fishing. Even when the weather is absolutely terrible, even then we may miss that big one.

Are There Any Exceptions to the Rule?

There are always exceptions to the rule. Sometimes the pressure is very high and fishing is great.  Then sometimes the pressure is very low and the fishing was horrible.

When the pressure is to high or very low, the fish won’t jump into your boat. So if the pressure is too high or low, then you should probably call the day off, the grass always needs cutting right?

Best Barometric Pressure for Trout Fishing: Summing it Up

The barometer is used to measure atmospheric pressure. It may seem like a small detail, but it actually plays an important role in catching fish. When fishing for trout, you need to be aware of the barometric pressure, but it isn’t the be-all-end-all if you should go fishing.  Use the information to help narrow your angling tactics.  The best barometric pressure for trout fishing is any barometric pressure, after all, any day fishing is a good day.