I'm not in Europe, but I understand that it's fairly common in some southern areas, but overall much less common then the US. Air conditioning is apparently more common for offices and stores than for residences.

Rolling out more air conditioning in Europe may not be a terrible thing from the standpoint of electricity providers. As things stand, unlike the US, where peak electricity demand is in the summer (due to air conditioning), Europe's peak electricity demand is in winter, due to electricity-driven heating. Having more-even seasonal demand probably makes life easier for the grid.

All that being said, I believe that the article is talking about unseasonably warm temperatures for October -- which is not that hot -- not so much extremely hot summer temperatures. This may not be a "roll out air conditioning" sort of thing.