We have a more extreme range of temperatures here in Switzerland, than we did in the UK.
This Summer we have rarely had days below 30 degrees, and in some places temperatures are regulary close to 40 degrees.
Nights have been warm too, and then suddenly in the past week the daytime temperatures are still around 30 degrees but night time temps have 'plummeted' to around 15 degrees!
It is wonderful for the cooler nights, but I have had to rush around and put light blankets back on all the beds, and this morning when my daughter came down she said it was freezing! But it will get to around 30 degrees today, and we will be swimming in the lake before lunch.
Winter temperatures can get as low as minus 10 where we live, and are always below freezing for several months of the year. Snow is common for at least a couple of months, and we are talking about several feet of snow - not just a dusting.
But having said all of that the houses here are generally very well designed, built and insulated.
We don't have air con, although we do have heating, and even on the hottest days, using careful airing and window shutters (which all houses have) the temperature inside never got above 21 degrees.
In Winter we have heating, but it is underfloor which quickly and efficiently heats the entire house, and the well insulated building maintains the heat very well.