If I had the kids with me, or maybe even better alone, and were having a vacation in Western Norway, I would consider stopping at Årdal and visit this place, simply the public outdoor swimming pools. There are even two, a few miles apart, in two different villages.
Looks like a pretty fine place to swim, if you ask me, if you enjoy the scenery. Outdoor swimming feels special, exactly because of the climate. The swimming season is normally short, but if you’re a little daring you can do it even in rather cold weather. The pool is anyway heated.
I’ve never used the pool in Årdal myself, the last time I was there I was 17 or something, on my way down from a hiking trip in the mountains. I have been swimming in an outdoor pool, though, for instance at Klækken hotell in Ringerike, where they have a small but fun pool where you can swim from the indoor to the outdoor part of the thing. Heated pool water and snow on the ground was really fun when I was there.
This is the pool in Øvre Årdal, which seems to be the most spectacular place, judging by the photo:
Information about the pools on the same site, unfortunately not in English:
It says to be open “all summer”, whatever that means. I would say normally May until August, but I don’t know how Årdal kommune defines the summer season…