The best conditions for ice fishing are when the barometric pressure is steady and high or immediately before it begins to fall. Barometric pressure is stable during mild weather and begins to fall with the approach of a storm or a weather front.
Other weather factors that can affect fishing, such as sunlight, wind and temperature changes, are unable to be detected by fish under a layer of ice. Fish sense changes in barometric pressure because they have an air bladder that makes them much more sensitive to weather changes than humans. A falling barometer increases the pressure on the air bladder, making the fish uncomfortable and less inclined to feed in normal patterns and water depths.