Some general rules regarding barometric pressure are:

Pressure Trend

Typical Weather

Fishing Trends

Suggested Tactics

High

Clear skies

Fish slow down, find cover or go to deeper waters.

Slow down lures and use baits more attractive to fish. Fish in cover and in deeper waters.

Rising

Clearing or improving

Fish tend to become slightly more active

Fish with brighter lures and near cover. Also fish at intermediate and deeper depths.

Normal and stable

Fair

Normal fishing

Experiment with your favorite baits and lures.

Falling

Degrading

Most active fishing

Speed up lures. Surface and shallow running lures may work well.

Slightly lower

Usually cloudy

Many fish will head away from cover and seek shallower waters. Some fish will become more aggressive.

Use shallow running lures at a moderate speed.

Low

Rainy and stormy

Fish will tend to become less active the longer this period remains.

As the action subsides, try fishing at deeper depths.

It is important to note that after a long feeding period, the action will slow regardless of the following conditions. On the flip side, a long period of poor fishing conditions may be followed by a really good one.

It is also important to note, that the barometric pressure is just one of many factors that effect fish feeding habits. Other effects include water temperature, light, tidal forces, water clarity, the pH level, water levels, wind/surface disturbance, boat traffic, fishing pressure, and so on. Another good judging factor of fishing is the solunar effects which play a role in the tidal and illumination factors.

As a general guideline, think of 30 inHg (1016 millibar) as being a normal level. World records vary from a high pressure of 32.0 inHg in Siberia to 25.7 inHg during a typhoon (both readings are off the scale of most barometers). For the US, extreme levels can be considered as 30.5 inHg and 28.5 inHg. When it comes to fishing, a change of just +/- 0.02 inHg from normal is enough to effect their feeding habits.

The effects of barometric pressure is greater in fresh and shallow waters, than it is in deeper waters. This is probably due to the fact that the pressure of water is so much greater in deeper waters making the air pressure above it no longer having any significance.
It's overlooked. Barometric pressure is usually overlooked by the average angler who's planning what days to fish this week or next, but it can be important. Especially so in springtime. Spring is a time of the season when barometric pressure can make or break a fishing trip. So, I'd like to give you a few pointers about barometric pressure and how to deal with it. This article will help you most if you have "flex time" that allows you to fish any day of the week. Then, you can basically avoid barometric highs if you find, like I do, that such periods are tough times to catch bass.

It's also deceptive because anglers often get the urge to make a few casts when it's "good" weather that's comfortable for us (bright, dry, clear skies) but this same high pressure pattern that's so favorable to us often means poor fishing. Meanwhile, the arrival of wet, stormy weather will cause many anglers to decide to stay home even though such inclemency, as uncomfortable as it is to us, can yield a bounty of fish!

Pre-frontal conditions. When the barometer is falling, you will usually have non-westerly winds. This is usually a good time to fish, but it usually also means some wet weather is on its way into your area. Southerly or southeasterly winds are usually harbingers of wet weather that will usually pass through quickly (albeit sometimes dramatically with heavy downpours and lightning). Northerly or northeasterly winds usually indicate slower-moving larger weather systems which will take longer to pass, and often trigger protracted feeding sprees before it's arrival.

Just before the wet weather arrives, it will be preceded by a "front" (an abrupt change in weather) which can often trigger feeding binges by bass before and during the frontal passage. Keep in mind, however, that fronts can be dangerous, especially ones with high winds and lightning -- not to mention getting soaked and possibly sick.

However, if you want to fish in one, it can be good to position yourself on a shore that has the wind blowing into it -- which often means the northwest shoreline. Try to get the wind blowing "into" something such as a small bay, a point, a dropoff where a shoreline flat slopes into deeper water for example.

Post-frontal conditions. Fair fishing will usually last for a brief period after the wet weather passes -- especially near mouths of feeder creeks. You should continue to do fine with the fish if the wet weather "tails off" gracefully without brisk westerly winds clearing the front out. However, if the wind quickly turns west after the front passes, this means that a high barometric pressure system is being pushed/pulled into the void left by the recently-departed low pressure wet weather. On such a west wind, you can sometimes expect this to cause the fish to get "lockjaw" and pull back (either out to the nearest deep water or into the closest heavy cover). This will often last 2-3 days before the west wind subsides and the barometric pressure stabilizes near normal.

In between fronts. At this point, the barometer and the weather may stabilize for a few days and you can usually expect the fishing to stabilize also. As the barometer starts dropping again for a day or two in advance of the next wet weather coming your way, fishing will improve! Then the whole cycle of pre-frontal low pressure, precipitation and post-frontal clearing will repeat itself.

The odds are in your favor. Just like in the lottery, it's a game of chance where you can win some and lose some! Fish don't always follow the same game plans we do, but the average springtime angler's odds are better to be on the water just before, just after and during the arrival of wet weather (when the barometer is dropping, bottoms out, and then slowly rises). Remember, you will find that "just before" and "just after" mean exactly that! If a low pressure front comes through in the morning, it may already be "too late" if a stiff clearing wind is blowing through by lunchtime!


The Best and Worst Conditions: Bass bite fairly well when the barometer is from, say, 29.98 to 30.02. However, from mid-spring to early autumn you may have your best catches, when barometric pressure has dropped from the 29.98 to 30.02 range, and dropped dramatically in a relatively short time. It's the drop of .10 to .15 in pressure (and especially a fast drop) that triggers two things: (1) the bass go on a relatively brief rampage, and (2) it's an approaching weather front that causes the air pressure drop. Of course, it can be hazardous to fish once the front gets too close, what with the probability of high winds and lightning. So a second game plan might be to fish a couple of days after a significant front has passed through, once air pressure has stabilized. And a third game plan would be to go fishing when the air pressure has been relatively steady for several days. The worst times to go fishing, in terms of barometric pressure, are when the pressures are below 29.90 or above 30.15. It is thought that bass tend to recover more quickly from air pressure changes in warm water than they do in cold, as much as three of four days in cold water, despite barometric pressures otherwise seeming to be fine. In conclusion, many environmental factors affect fish behavior, like PH, water clarity, water temperature, water fluctuation, just to mention a few. But changes in barometric pressure are critical, and understanding them will help you concentrate your best bass fishing efforts even more.