top of page

Understanding Feeding Behavior of Fish: How the Weather and Moon can Influence Fishing Success

Weather is one of the biggest drivers of fish behavior and often determines if fish are actively feeding or stubbornly shut down. Changes in air temperature, barometric air pressure, wind speed and direction, cloud cover, UV index, and precipitation don’t just affect anglers’ comfort; they reshape light levels, oxygen and temperature layers, water clarity, and the movement of baitfish and insects. When conditions shift, fish adjust where they hold, when and how far and long they roam for food, and how willing they are to strike a bait or lure. 

​

The moon can also impact fish feeding behavior.  Moonrise, moonset, and moon overhead/underfoot times, often referred to as "feeding periods", can trigger increased fish activity and feeding, while the moon phase and level of illumination can influence nighttime light levels, predator confidence, and when baitfish and insects are most active. On this page, we’ll go into more detail about how the weather and moon can impact fish behavior and why using weather forecasts and lunar data can help you plan when to fish.

Temperature

Fish are ectotherms, so temperature controls metabolism, digestion rate, and activity. It is the single biggest driver of feeding frequency.

Rising temperature trend 

  • More active fish and more time spent feeding (until temperatures exceed the upper limit of their optimal range).

  • Fish often move shallower in spring because shallow water warms first.

Cooling temperature trend ​

  • Cooling often arrives with cold rain, wind shifts, and/or fronts which can de-stabilize a fish's environment and make feeding less likely.  Largemouth bass are especially known to "turn-off" when a sudden cooling trend occurs, especially in the spring. 

Steady temperature trend (stable)

  • Fish settle into repeatable and more predictable depth/structure patterns.

  • More consistent and predictable feeding behavior.

Barometric pressure

Barometric pressure is associated with fish behavior through various mechanisms. Fish can sense barometric pressure changes through their swim bladder, so changes in pressure can affect behavior.  The depth of zooplankton and small prey items, such as insects, is affected by barometric pressure and can affect feeding activity of larger prey species. Finally, changes in barometric pressure often accompany other weather-related phenomenon that can impact fishing, including cloud cover, wind speed and direction, precipitation, and temperature shifts.

Falling barometer (approaching low pressure / pre-front)​

  • Increased feeding, increased movement, especially as wind and clouds reduce visibility. 

  • Widely viewed as a prime time to target several gamefish species, especially muskie and pike.

​Rising barometer (post-front high pressure)

  • Fish become less active, hold tighter to the bottom, and seek structure, especially with clearing skies, brighter sun, and calmer conditions.

  • Feeding may resume after barometric pressure stabilized.

​Steady barometer (stable weather)

  • Fish settle into a predictable, active feeding routine, especially with steady wind direction. 

Cloud cover

Cloud cover controls light level, which strongly affects fish movement and feeding patterns. 

Cloudy/overcast

  • Often associated with more day time roaming and feeding activity as fish are more confident and less easily spooked. Feeding periods are longer. This is especially true if there is a chop in the water.

Sunny/clear

  • Feeding activity generally slows; fish can become more picky and less confident to roam for prey. 

  • Feeding may be more likely in the early morning or evening periods. This is especially true in calm conditions and in species of fish especially suited for actively feeding in low-light conditions, such as walleye and catfish. 

UV index

Many species of fish possess specialized ocular receptors that detect ultraviolet light. Depending on the intensity of UV light (UV index), fish may alter their location and behavior due to stress.

Lo UV index

  • More comfortable conditions promote increased feeding activity and larger roaming areas.

High UV index

  • Reduced feeding due to stress, especially in certain species sensitive to high UV-B radiation, such as salmon and trout. 

  • Fish may move deeper and to areas providing shade and comfort.  The area and time for roaming for food is reduced.

Wind speed and direction

Wind is one of the most important day-to-day fishing variables because it can impact light penetration and water currents, both of which can influence feeding activity. 

Calm wind (e.g. 0-3 mph)

  • Reduced feeding due to increased light penetration and reduced gamefish confidence in active feeding behavior.

  • Fish may move deeper and to areas providing shade and comfort, depending on cloudiness and water clarity.

  • Roaming area reduced.

Light/moderate wind (e.g. 4-10 mph)(enough to create a light chop)

  • Provides some level of confidence/security to predator fish, increasing feeding activity and aggressiveness.

  • Roaming area increased.

  • Food chain can become energized as wave action increases oxygen levels, stirs up plankton, and concentrates prey items, such as baitfish, into predictable locations.​

Strong winds (e.g. >15 mph)

  • May create too much wave activity, creating stress for fish, and reducing feeding activity.

  • Fishing becomes much more difficult as maintaining contact with the bait is more difficult.

  • Water clarity can become significantly reduced. This is especially detrimental for species sensitive to high turbidity, such as smallmouth bass.

Consistent direction (same general direction for past day or two)

  • Usually associated with stable weather conditions, which promote active feeding.

Inconsistent direction (frequent changes in direction)

  • Creates instability in the fish's environment and erratic distribution of prey items, leading to reduced feeding activity and less predictable behavior.

Easterly winds

  • Often associated with a high pressure system, that can bring suddenly cooler weather, clear skies, and high barometric pressure, all of which can make fish more cautious and less active feeders. As the old adage goes, "Wind out of the east, fishing is the least".  

  • If winds are light to moderate or if fishing is done early in the morning or in the evening, the negative effects may be reduced, as the chop and reduced sunlight can help mitigate the clear skies.

Moon (lunar) influence

The moon can impact fish behavior by providing nighttime illumination and imposing gravitational pull.

Moon phase (illumination)

  • Moonlight can shift feeding timing (more night feeding under bright moons).  Largemouth bass, walleye, and muskie are especially known to increase night feeding with a full moon.  

Major and minor feeding periods (solunar periods)

  • Major feeding periods: Periods when the moon is at its highest point overhead or lowest point underfoot associated with tides, increased baitfish and invertebrate (insect) movement, and increased gamefish feeding behavior.  

  • Minor feeding periods: Times when the moon crosses the horizon (moonrise or moonset) that are also associated with increased prey movement and gamefish feeding activity.

  • If either major or minor periods occur during sunrise or sunset, the effects can be greater. 

With so many weather and solunar variables that can impact fishing success, it's nearly impossible to look at a standard weather forecast to determine the best days and times to fish.  That's why the FishCaster mobile app can be one of the most important tools you can use to make you more successful on the water.   
Download now!

References

  1. Fry, F.E.J. (1971). The effect of environmental factors on the physiology of fish. In W.S. Hoar & D.J. Randall (Eds.), Fish Physiology. Academic Press.

  2. Magnuson, J.J., Crowder, L.B., & Medvick, P.A. (1979). Temperature as an ecological resource. American Zoologist, 19(1), 331–343.

  3. Coutant, C.C. (1977). Compilation of temperature preference data. Journal of the Fisheries Research Board of Canada, 34(5), 739–745.

  4. Wetzel, R.G. (2001). Limnology: Lake and River Ecosystems (3rd ed.). Academic Press.

  5. Imberger, J., & Patterson, J.C. (1990). Physical limnology. Advances in Applied Mechanics, 27, 303–475.

  6. Helfman, G.S. (1993). Fish behavior by day, night and twilight. In T.J. Pitcher (Ed.), Behaviour of Teleost Fishes. Chapman & Hall.

  7. Häder, D.-P., et al. (2007). Effects of solar UV radiation on aquatic ecosystems. Photochemical & Photobiological Sciences, 6, 267–285.

  8. Wurtsbaugh, W.A., & Neverman, D. (1988). Postulated effects of barometric pressure on fish behavior. Fisheries, 13(5), 26–28.

bottom of page