I'm living in Vienna, having grown up in this city. I can assure you that while the city has grown, it actually put a lot of effort into primarily increasing population density instead of growing into the countryside (well, they have expanded too, but not by much in comparison to the population growth). The extra heat does not come from more concrete here - Vienna is one of the greenest large cities in Europe, and with lots of forest surrounding the west and the river going through it is a pretty privileged situation overall. Also, this year for example i can count the amount of days below 0°C on one hand - i haven't seen ice in any meaningful amount. All together i'd say our temperature window has shifted by around 10°C upwards since the late 80.

Edit: Just looked it up, it really seems like the average didn't move as much as the temperature maxima/minima.