I've done it in 15 F. I think -25 would put you in shock![]()
Just found this picture of the first Q Pool Customer in - 25 F weather:

The place I stayed at in Park City a few years back had a inside-outside pool connected by a glass door (like a partially closed garage door). It was about 30 F outside, so even though I stayed in the water the entire time I did not linger outside too long before swimming back inside.
I've seen conflicting information as to if the Burke Pool will be year-round or not. Just because a pool is heated does not make it suitable for winter use. And, again, think of all the energy being consumed just to keep it warm...even with a solar blanket/cover.