It is an average over all the seasons, including Nordic (60 deg N) winters with associated snow & slush.
The car is pretty similar to drive as the electrics. The hybrid drive is indeed electric, although there is some mechanical by-pass from the petrol engine to the drive shaft.
The environmental effect of electric cars depends much on how the electricity is made. The total efficiency of a combustion power plant, electric power transmission and battery charge/discharge efficiency is somewhat less than a Prius-type hybrid drive. The net effect will be transferring the emissions from traffic to the power plant.