Water boils at 212 deg F at sea level, of course, but the
boiling temperature of pure water is a pretty strong function of the ambient pressure. This figure shows the boiling temperature of
water at different pressures.
Atmospheric pressure at sea level is around 14.7 psi, and that point is
marked on the figure with a red circle. The standard operating pressure for pressure cookers is 15
lbs which means 15 psi above atmospheric pressure. That point is marked with a green triangle in
the figure. You can see that the boiling
temperature for water is around 250 deg F inside a pressure cooker operating at
sea level.
