Fishing & Weather

The earth consists of two pressurized environments (Air & Water). Sensible weather, the day-to-day weather that we experience everyday is one of many factors that affects fishing as well as our daily lives. Weather changes are caused by atmospheric changes in pressure (barometric pressure) driven by the fast moving river of air called the jet stream located at about 30,000 feet in the atmosphere!

A basic rule is that rising air (falling pressure) produces clouds and even the possibility of rain and snow. Sinking air (rising pressure) means clouds and precipitation development is suppressed, and usually brings clear skies and fair weather.

Weather conditions do impact the catch rate indirectly of the species you are pursuing, and will depend on various interdependent factors such as: availability of fish, water depth, temperature, clarity, wind, and barometric pressure (The measurement of weight of the atmosphere above us)

Water Systems are pressurized environments. Water is much heavier than air. A cubic foot of air weighs 1/12 pound (lb). A cubic foot of fresh water weighs 62.4 lbs and a cubic foot of sea water weighs 64 lbs. Water pressure, like air pressure, is a function of weight; the deeper one goes the greater the surrounding water pressure. Therefore, the direct effects of changing barometric pressure (air) is greater on fresh shallow water species than deeper lakes or oceans where the depth of the water inhabited by deep water species makes the air pressure variations insignificant.

Air pressure and other variables:
The air that surrounds the earth is constantly placing pressure on the earth’s surface. As the jet stream drives the large areas of high and low pressure on the surface of the earth, these large pressure systems then in turn, drive the large-scale wind flows at the surface levels.

As air inherently wants to move from higher to lower pressure (the reason why air wants to escape a bike tire and not vice versa) it will converge in a counter clockwise manner around low pressure, and diverge in a clockwise manner around high pressure.

This is because the Earth is rotating and the Coriolis force (the deflection to the right of one’s motion on large special scales) results in the observed surface winds. These resulting surface wind flows create weather fronts, which are distinct boundaries from say cold-dry Canadian air, and warm-moist Gulf of Mexico air. There are three basic types of fronts: Cold, Warm, and Stationary.

Typically, low pressure is the “parent” system for these frontal systems, with cold fronts often extending from the center of low pressure and orientated to the south and west of the low center. Warm fronts often extend from the low center and are positioned to the east and north of the low center.

When a warm front passes, pressure still tends to fall as the warm front is often out ahead of the low, meanwhile, when a cold front passes, pressure tends to rise because the low center has already passed, and high pressure is building. Understanding a front’s make up and the weather they bring is key to predicting weather events.

Cold Fronts: (High Pressure)
As a cold front passes the air pressure tends to rise (air sinks) as colder and drier air typically resides behind a cold front, which is more dense than warm-moist air, this can be recognized by clearing skies after inclement weather. Also, you may notice strong northerly winds after a cold front passes.

This is because of the clockwise wind flow around higher pressure, coupled with a large change in pressure between the relatively close area of lower pressure, and the impending area of higher pressure. These abrupt weather changes disturb the environment, and most game fish will seek deeper water and or cover becoming inactive. The cold front effect on fishing lasts 1-2 days before another front moves in or the weather stabilizes.

If your fishing in a cold front here’s a few suggestions: If possible fish small dark water lakes or rivers rather than clear deep lakes. Live bait is the preferred choice with a slow presentation; vertical jigging or slip bobbers are the best. Fish near the bottom or in weeds, around cribs and rock piles. As cold fronts bring lower air temperatures reducing the water temperature fish during midday when the water is the warmest.

Warm Fronts: (Low Pressure)
When a warm front approaches the air pressure is low, warm, moist air is rising and moving counterclockwise toward the center, creating less pressure. Because of this, a barometer usually shows falling pressure as a storm system approaches.

Fish sense the drop in air pressure and become active, some fishery biologists attribute the increase of feeding behavior from atmospheric reduction in pressure that affects their air bladder another opinion is fish use vision as a primary feeding sense, as a storm hits with heavy winds this churns the water making it cloudy and more difficult to feed.

Here are some fishing tips during a low-pressure front: Cloud cover and rain is associated with low-pressure fronts, these reduce sunlight causing fish to move higher in the water column. Use surface and shallow running lures over weed beds, weed edges, and over open water if schools of baitfish are found. Faster retrieves are recommended, as fish are active.

If storms become intense with thunder and lighting fish will become less active or “spooked” by these conditions and move to deeper water. From a safety point you should never fish during a lighting storm. Lighting may strike many miles from the center of the storm. Take shelter upon an approaching storm fishing rods make ideal lighting conductors.

Stationary Fronts:
A stationary front is a weather boundary between two different air masses (fronts) in which neither is strong enough to replace the other. They tend to remain essentially in the same area for extended periods of time. A wide variety of weather can be found in a stationary front ranging from sunny and fair to cloudy and even prolonged rain.

Stationary fronts can focus lift in the atmosphere and can actually help develop areas of low pressure along them. This process results in the stationary front morphing into a warm front on the east side of the newly developed low and a cold front on the west side. This means that even stationary fronts can change with time and should be monitored for future implications on your luck out on the water.

Fishing during a stationary front rates good to excellent. Barometric pressure remains stable for an extended period of time. Fish develop a comfort level and a feeding pattern. Find the pattern of the specie your pursuing and your catching fish. Most fishing presentations work during this period. Best Fishing Times (Solunar – Moon Phase Tables) are based on using stable weather conditions.

Wind & Clouds:
As the wind related proverb says “When the wind is east the fish bite the least, when the wind is west the fish bite the best.” Wind is an influential factor in fishing behavior as it stirs the food chain, provides oxygen and cover from the sun with wave action. Constant wind blowing from the same direction over days will migrate game fish on the windy shoreline to feed on baitfish.

Water temperatures will increase also as the surface water is pushed by the wind. This is especially helpful in Spring and Fall seasons as the angler seeks the warmest water. Westerly and Southern winds are proven to produce the best fishing results as the proverb states.

Clouds and cloudy conditions have similar effects as wind by reducing sunlight on and near the surface. Light sensitive fish will become more active, a combination of light wind (chop) and cloud cover condition is excellent for surface lures.

Thanks to Luke Sampe Chief Meteorologist of WJFW Rhinelander WI. for his contributions on this page.