Work out atmospheric pressure at altitude instantly with clear inputs, formula shown and shareable results.
The barometric formula for the standard troposphere gives pressure as sea level pressure times (1 - 0.0065h/288.15)^5.25588. At 2500 m that is 747 hPa, 74% of sea level, and water boils near 92 C. Pressure halves roughly every 5500 m, which is why supplemental oxygen becomes necessary above about 3500 m.
Barometric formula
P = P0 (1 - 0.0065 h / 288.15)^5.25588
Boiling point
falls about 1 C per 300 m of altitude
It is gM/(R x lapse rate) for the standard atmosphere, which is what integrating the hydrostatic equation with a linear temperature profile produces.
Because the lower boiling point limits temperature. At 2500 m water boils at 92 C, so simmering is 8 degrees cooler.