An all-sky scanning Fabry-P¿rot spectrometer was used to observe temperatures of auroral OI (557.7-nm) emissions over Poker Flat, Alaska (65.12N, 147.43W). The sudden temporal and spatial changes in Doppler temperatures observed are likely owing to the emission height changing as a response to variations in the characteristic energy of the precipitating electron population. Three cases were analyzed: (1) A Doppler temperature drop (~200 K) over the entire sky occurred immediately after an auroral brightening; the temperature remained lower after the auroral intensity had resumed its quiescent levels. (2) A local increase of Doppler temperature, colocated with a weak auroral arc, occurred 25 minutes before a westward propagating substorm onset. When the auroral luminosity suddenly increased the Doppler temperature had a sharp decrease. (3) The region inside a loop-like auroral arc showed elevated Doppler temperature relative to that of the arc itself. Auroral fading prior to onset was accompanied by increased temperatures.