The 3-hour Kp index is examined as a function of the average GSM latitude of the interplanetary magnetic field (IMF) for 'away' and 'toward' sectors. The data are comapred with the Russell-McPherron model for the semiannual variation in geomagnetic activity. For the 4-year period examined it is found that the measurements are in agreement with some features of the model. The most striking feature of the data is the difference between away and toward sectors; this difference is discussed in terms of an annual variation in geomagnetic activity.