From the online Collins English Dictionary we get the following definition: “The weather is the condition of the atmosphere in one area at a particular time, for example if it is raining, hot, or windy.” As far as definitions go this seems pretty straightforward, but when it comes to fishing, things are seldom that simple. So how does weather affect fishing?

In this article I want to take a look at different weather conditions and the impact they have on a fishing excursion. The saying: “There’s more than meets the eye” definitely has a bearing on weather conditions during fishing trips, because of the various permutations inherent in weather conditions.

Again I have to emphasize that I am not a weather expert by any stretch of the imagination. What follows in these pages are purely observations and experiences coupled with bits of random knowledge that I have accumulated through many years spending outdoors while on numerous fishing trips.

Now, with that off my chest, I think it is prudent to start with, in my opinion, one of the most important factors influencing fish behaviour namely air pressure (or barometric pressure, more specifically). You will notice that this factor will feature quite prominently in this article.

How Does Weather Affect Fish?

Barometric Pressure

With more and more experience anglers may become more successful in predicting the outcome of a potential fishing trip due to, amongst other things, gaining knowledge about the prevailing weather conditions at that specific time.

However, even the most astute and experienced fisherman can get it wrong from time to time due to changing nuances in barometric pressure which sometimes makes it difficult, if not impossible, to accurately determine the situation based on existing weather conditions.

This can give rise to the (seemingly) contradictory situation that you fail to catch any fish when expecting to, or catching bucketsful after having all but given up on the day because of inclement weather.

One common denominator amongst all bone fish species is that they possess a swim bladder. Amongst scientists there is a theory that those early swim bladders eventually evolved into the lungs of earth dwelling vertebrates when our ancient ancestors decided to leave the ocean to try their luck on dry ground.

The swim bladder seems to fulfil a vital role in, amongst other things, fish mobility and, more specifically, their movement in a vertical plane in the water column. By inflating or deflating this organ, they can effortlessly ascend or descend while using the minimum of energy. It also dictates in a big way the feeding patterns of most fish species that I come into contact with.

One has to keep in mind, however, that the air pressure under water increases almost exponentially the deeper you venture. At this point I also want to emphasize that I am neither a meteorologist nor a fish biologist! Having said that, it seems to me that most bone fish species are able to detect variations in weather patterns caused by barometric pressure.

Rainy Days

The way I understand it is that a low pressure weather system basically means a weather system containing more moisture (that’s why the air pressure is lower). High pressure conditions are generally associated with nice weather, while low pressure is generally associated with cloudy, rainy, or stormy weather.

In my experience, once a low pressure weather system (or cold front, as I know it) is on its way the best time to go fishing is about 24 hours before the barometer starts dropping. If it gradually descends the fishing will still be good, but once there is a dramatic downward spiral in barometric pressure most fish species seem to go off the bite.

At the height of a storm or a spell of inclement weather, and as long the air pressure remains relatively low, conditions for fishing are generally poor.

If the intrepid angler is in possession of a bit of patience and maybe even a barometer he or she needs not despair for too long. In the normal course of events, and depending of the severity of that specific weather system, nature will endeavour to restore atmospheric equilibrium at the earliest opportunity.

In practical terms it means that the observable weather conditions may not change that much compared to what’s happening to the barometric pressure in the atmosphere. If the centre of the weather system passes your fishing locality, the barometer will start climbing again.

The significance of this phenomenon is that, even though it may be still cold, windy and even rainy, once the barometer starts rising again you are good to go.

Sunny Days

A friend of mine’s dad used to say that bright, sunny days are excellent for spending a day at the beach, but definitely not a good sign for a successful fishing outing. I will admit that it is a bit of a sweeping statement, but I am in general agreement with this sentiment.

Under most circumstances bright, sunny days can prove to be very challenging to potential anglers whether it be on a stream, lake or at the sea. Due to the amount of sunlight in the water fish normally tend to seek protection in deeper places. Therefore, most shallows, which would normally attract them because of the availability of food, may become devoid of any fish life.

When fishing freshwater lakes or ponds a good tactic would be to focus your attention on those spots obscured by water plants or any other shady and protected areas. Also be on the lookout for deeper holes and submerged trenches or drop offs where there is less penetration of sunlight.

Fish will instinctively head for those places in order to avoid the eyes of hungry predators or to camouflage themselves for an ambush on unsuspecting prey.

Furthermore, whenever you intend to fish a stretch of water on a clear, sunny day remember to approach cautiously and tread lightly, always keeping in mind that fish are adapted to detect vibrations as well and any excessive and/or unnecessary stomping on the bank will put them even more on the alert.

Having said all that one has to keep in mind other factors that may also play a role. If it is the first cloudless, sunny day after a cold front has passed, the barometer will be rising and this, combined with maybe a bit of discoloured water, may provide excellent fishing conditions.

Windy Days

Generally speaking most people are not too fond of the wind. There seems to be something about an invisible force endlessly pulling and tugging on your clothes, blowing your hair all over the place and constantly kicking up dust and dirt that the bulk of the population finds quite irritating.

However, the good news for all prospective anglers out there is that the wind can be one of our closest allies when it comes to determining fishing success. Again I have to emphasize that barometric pressure will also play a role here. If the wind is an indication of a low pressure system advancing, the barometer will be falling rapidly with a negative impact on any fishing efforts, as already pointed out.

Please note therefore that the following few paragraphs will describe windy days where there are no significant changes in the air pressure.

Firstly the wind can play a significant role in determining where fish will feed, be it in a lake, dam, pond or the ocean. If we turn our focus on freshwater impoundments it is not that difficult to notice that a persistent wind, with accompanying wave action, will eventually transport most items in the upper surface layer to one side of the lake.

These may include both miniscule organisms like phytoplankton and zooplankton as well as terrestrial insects of all sorts. The next logical conclusion to be made is that the fish will follow the food which, in turn, makes the decision about where to concentrate your fishing efforts a bit easier.

Moving over to windy conditions at the seaside, things can get a little bit more complicated. I used to live close to the beach in False Bay, South Africa and, at a certain time of the year, the wind from the south east is the harbinger of good fishing.

The reason for this is the following: Due to the fact that False Bay faces in a southerly direction the waves rolling in from the deep ocean do so from a western/southwestern angle.

Once the southeaster starts blowing, its opposing force influences the wave action to such an extent that diatoms and other microscopic items are stirred up from the bottom giving the water a murky colour and creating favourable feeding conditions for a host of resident and migratory fish species.

I normally waited until the second day after the southeaster started blowing to put on my wetsuit, grab my gear and head out to my favourite rocky outcrops for some serious fishing.

On the other hand, winds from different directions may blow the warm surface water away which then results in an upwelling of cold water from the depths which can have a negative impact on fishing. The best advice here is to become familiar with your fishing area as soon as possible in order to differentiate between the winds signalling good fishing conditions and those which don’t.

Finally, let’s take a brief look at the effect of wind on the clarity of the water.

On sunny and windless days the water in a lake or dam can get very clear due to a lack of water movement which allows most of the sedimentary particles to float down and settle on the bottom. This normally results in a dramatic improvement of water clarity with subsequent detrimental impact on your fishing.

Predatory species, especially, tend to avoid clear water conditions because it seriously hampers their hunting strategies. If the prey can spot them from afar they lose that vital element of surprise in order to enjoy a decent meal.

It is furthermore easier to spot an angler on the lookout for his or her next meal and that is why a good surface chop can be of such an advantage to an angler. It emboldens the fish to go searching for food and also conceals the person carrying a fishing rod.

Cloudy Days

Any significant amount of cloud cover dramatically decreases the amount of sunlight in the water thereby creating the same conditions that can be ascribed to fishing on windy days, early in the mornings or late afternoons. These are, normally, the times when most predatory fish go hunting.

However, and in line with the general theme of this article, keep in mind what causes the cloudy conditions. If the clouds are the advance guard of an impending low pressure system the fishing may not be that good. However, if the barometric conditions remain relatively stable, you can go fishing with quite some confidence.

Hot and Cold Days

Because they are cold blooded creatures, any variations in temperatures in their immediate environment have a significant effect on the behaviour and activities of most fish species.

Depending on their species fish have a specific window of minimum and maximum temperatures where they operate optimally. In the event of temperatures dropping or rising outside the parameters of this comfort zone (either becoming too hot or too cold), that specific fish species will cease its normal routine and/or behaviour or depart for locations more amicable.

For example: Bass thrive in water temperatures ranging between 60 and 75 degrees Fahrenheit ( 15,5 to 23,8 degrees Celsius) whereas rainbow trout prefers temperatures ranging between 44 and 61 degrees Fahrenheit (7 to 17 degrees Celsius).

Also, a dramatic drop in temperature, although happening within the parameters of a particular fish species comfort zone, may cause unfavourable conditions for the species involved to such an extent that they may lose any and all interest in taking your bait.

From a weather perspective it is therefore important to observe not only the weather conditions on the days that you intend to go fishing, but also some time prior to that. Any heavy rains in a specific area can cause an increased influx of fresh, cold water into fresh water systems like dams, ponds, rivers or lakes. As a result the water temperature may be lowered substantially in a relative short period of time thereby creating adverse fishing conditions.

However, if the temperature gradually changes over the course of a few days it gives fish more time to get use to the changes and the impact on your fishing efforts will certainly be less dramatic.

Also keep in mind that colder water contains more oxygen than warm water and is therefore, generally, conducive to increased fishing activity. On a hot summer’s day the water temperature in a closed body of water can rise to such a degree in most parts that the piscatorial inhabitants of that location become lethargic and lose all interest in almost any kind of activity.

One tactic to overcome this specific problem is to actively look for the deeper spots with less sun penetration. The water will be markedly cooler in those areas and you will find that a lot of fish will also find those spots much more agreeable. That will, generally, increase your chances to be successful.

If you are fishing on a river on a particularly hot day, focus on the fast water and rapids – areas which will be well-oxygenated due to constant water movement.

A thermometer is a simple yet effective device which most people seem to overlook while packing equipment for a fishing trip. Once at your fishing location it will take very little of your time to ascertain the temperature in different locations.

Although this may seem like a purely academical exercise on that specific day, once you have made proper notes adding weather, cloud cover, wind etc. into the equation (as well as number of fish caught!) it can be a very useful tool for future fishing trips.

If we turn our focus to the ocean again, one has to keep in mind that wind and sea currents also play a dominant role in determining the water temperature of a specific location at a specific time. These currents, aided by wind and wave action, are constantly shifting vast volumes of water from one place to another.

For example, a considerable amount of warm surface water, aided by these agents, can travel to a different place (with relatively cold water at that time) thereby influencing the fishing in the latter quite considerably.

Final Thoughts

Well, in the beginning of this article I warned you that the weather is a bit of a tricky customer when it comes to fishing! Hopefully some of the stuff I have written make sense to you or, better yet, some of you are able to identify with the observations and facts herein.

Like most other interesting things in life, fishing still remains a bit of a gamble. If all the stars are aligned (so to speak!) and the weather conditions proved to be favourable, it can be a very satisfying experience. More often than not though this is not the case, but there is always the opportunity to learn when spending time next to the water.

Note the conditions, environmental factors, temperatures etc. and make a mental note for future campaigns and also to further enhance your fishing library.

Bonus – This Alaskan Fishing Boat Does Not Answer to Storms