The scope of the study focused on tool speeds-plate temperatures at joining aluminium alloy and copper plates. The AA7075-T6 aluminium alloy and pure copper were welded using friction-stir welding (FSW) technique. The temperature variations of plates from stirred zone were detected using thermocouples installed at equal distance on both sides of the axis of the pin linear displacement. The temperature distribution in the surroundings of the welded zone was investigated. The effects of tool rotational speeds on plate temperatures were determined using such welding parameters of three tool rotational speeds of 660, 920 and 1500 rpm at a constant welding speed of 32 mm/min.