A good friend in the neighborhood where I grew up in Saskatoon has an in-ground pool.
I’m getting an in-ground pool in a few weeks. Sure, I can only use it for maybe 3 to 4 months of the year, but most summers are quite warn here in the Ottawa area. this summer’s off to a stinker of a start though: very cool and rainy.
Yes, but I’m not talking about neighbourhood pools. If you go in the suburbs, like the West Island, Laval, the north shore, almost everyone has a pool and a good proportion of those are in-ground, which you can clearly see in Google Maps. I, myself, know several people who own in-ground pools. Some of them are rich, but others are just regular middle-class folks.
The reason you don’t see private pools in the more central areas is simply because there isn’t enough room to build them.
I spent a good portion of my life living either in or around Montreal and I always associated the suburbian areas with pools.
But you UK guys cheat. You’re supposedly warmed unnaturally by the Gulf Stream. That’s our heat you’re using! 
Here, very close to the 45th parallel, outdoor pools are not common. But I live in a near-island county with 300 miles of freshwater coastline, not to mention numerous inland lakes. If I want a refreshing dip, I just walk out to my back yard and step into Lake Michigan.
Out of curiosity, I checked out some real estate adds. I found:
A house in Chicoutimi..
A condo in Val D’Or.
A bungalow in Alma.
A house in Dolbeau.
All of these places have in-ground pools and are situated in rather northern Quebec towns. You can check their locations on this map: