Weather plays a critical role in smallmouth fishing. Your odds are definitely best during a period of stable weather. Changes in the weather disrupt the smallmouth’s feeding schedule, so peak feeding times are not as predictable. How these changes affect them depends on the time of year, type of water, and type of cover.
Smallies generally bite better under overcast skies. Though they aren’t as light-sensitive as walleyes, low light causes them to move into shallow water and feed more heavily. However, in the early spring clear weather can urge them to feed as the sun warms the water.
The water clarity also plays a role in the degree to which cloud cover will affect smallmouth fishing. In gin clear water the fishing will tend to be poor during sunny days as they do much of their feeding at night. In moderate clarity, they feed sporadically even if the skies are clear.
Windy conditions usually spell good smallmouth fishing. The resulting waves scatter the light rays, allowing less light to penetrate the surface. This causes their feeding to increase, though a strong wind on shallow water can make it so murky they can’t see to feed. If the smallies are hanging in the weeds, the movement of the vegetation can also make them especially wary.
Rainy weather generally improves smallmouth fishing, especially if the surface is calm. The droplets decrease the amount of light that penetrates and the sound seems to reduce your chances of spooking the fish. If it’s windy the rain has practically no effect.
One effect rain also has is it washes off docks, which usually results in tiny particles dropping into the water, which are of particular interest to baitfish, who often start feeding heavily. You can guess who's interested in the baitfish...
A warm rain in early spring can be a game changer, since the water temp may rise several degrees in one day. This results in an insect hatch which serves as a wake-up call for semi-dormant smallmouth to start feeding.
A heavy rain usually means poor fishing, especially in streams as the rising water spreads the fish over a larger area. Runoff also clouds the water so they may not even see your bait. Storms with lightning cause them to stop biting for several days afterward if the storm is severe.
Smallmouth often go on a feeding spree before a storm, but if the temperature crashes and skies clear afterward the bite becomes tough. These negative effects are most noticeable in spring and summer, especially if they follow a stable weather pattern. Since they fed heavily before the storm they can afford to stop for a few days while the cold front passes.
In the fall, cold fronts will not typically slow feeding, as the fish seem to sense the onslaught of winter and feed more heavily. All the effects of cold fronts are more severe on clear lakes versus murkier lakes or in rivers.
Changes in barometric pressure can trigger feeding frenzies in fish. It’s widely understood that an impending storm or cold front will cause the pressure to fall, while improving weather conditions are accompanied by rising pressure. The falling pressure that precedes a storm is the cause for the improved fishing conditions, and rising pressure can shut down the bite. But why?
There are two adaptations that fish have that are affected by barometric pressure - The swim bladder and lateral line.
The swim bladder is an organ similar to the stomach, which can inflate with air and allows the fish to achieve buoyancy. As the air pressure changes, so does the pressure on a fish’s swim bladder. It’s something like a natural barometer.
The lateral line is a row of pores that runs from its gills to its tail. The fish use it to navigate and sense the presence of predators or food. It senses the tiniest of reverberations in the water, and as such, it is very sensitive to pressure changes. This is the organ that picks up the vibrations of your crankbaits.
Given these factors, it’s easy to understand how the barometric pressure can have a significant effect on the smallmouth behavior. Bear that in mind when hitting the water.
So in conclusion, choosing the right time is key to finding a smallie bite. Pick a day that is in the middle of a stable weather pattern, (preferably overcast), or the period leading up to a storm. In both cases you’ll find a fairly willing bite, and one of the most exciting fights you can experience in freshwater. Now go get ‘em! -WR