This scene reminds me of being at Landmannalaugar in 1974. It was in June, but the air was very cold and windy (not unusual in Iceland).
We had a chance to swim in a natural pool that was fed from one side by hot springs, and from the other side by melt from a glacier.
This meant that you could easily move around in the pool to find just the right temperature.
And there was a Northern Phalarope swimming in the pool with us.
The hardest part was getting out of the pool into the cold wind.