The effect of the By component of the interplanetary magnetic field on the polar daily magnetic variations are examined by using magnetic records from the International Magnetospheric Study Alaska meridian chain of observatories. A large difference (~180 ¿) in the direction of the disturbance vectors in the 9--13 MLT sector between 75 ¿ and 85 ¿ in magnetic latitude is clearly seen in the daily records. The results are in agreement with the earlier studies, which indicate that this difference in direction depends on the sign of the interplanetary magnetic field By component.