We present observations of a seasonal variation in the occurrence frequency of upflowing ions beams near 1 R_E altitude in the 1800–2400 local time sector. These observations were obtained from the Toroidal Imaging Mass‐Angle Spectrograph (TIMAS) instrument during POLAR satellite perigee passes from March 1996 to September 1997. We show that the observed variation is most simply interpreted as a variation in the magnitude of the auroral acceleration process responsible for creating upflowing ion beams and precipitating energetic electrons. These observations, the first to find a seasonal effect in the occurence of ion beams, also confirm previous reports which examined related phenomena and provide further evidence that changes in ionospheric conductivity have a measurable effect in the strength of the interaction between the Earth's magnetosphere and ionosphere.