Even light rain contaminates the purity of the air flowing over an airfoil. The mist of water mixes with the fastest-moving air, reducing its density and velocity. In turn, lift is reduced, also. Heavier rain moves the problem beyond the moderate impact of water splashing into the airflow.

Yes, rain can significantly impact aircraft performance in 2026, primarily through aerodynamic degradation and reduced ground friction. When flying through heavy rain, water droplets create a thin, roughened film on the wings and fuselage, which disrupts the smooth "boundary layer" of air. This roughness can increase aerodynamic drag by as much as 40% and reduce lift by up to 20%, essentially making the aircraft heavier and less efficient in the air. Furthermore, heavy rain can lead to an increase in stall speeds and a decrease in the "stall angle of attack," meaning the plane can lose lift more easily than in dry conditions. On the ground, rain creates the risk of hydroplaning (aquaplaning), where a layer of water prevents the tires from making contact with the runway, drastically increasing the required braking distance. Modern pilots are trained to adjust their takeoff and landing calculations to account for these "wet" performance penalties, ensuring safety even in torrential downpours.