Altitude

See what changes higher up.

YOUR INPUTS

Save a scenario to keep these inputs.

YOUR SCENARIOMETRIC UNITS

READ THE LIMITS

A standard atmosphere, not today’s weather

Pressure comes from the International Standard Atmosphere; weather systems move it by several hectopascals. The lapse rate is a chosen assumption: inversions, sun, wind and valleys break it. Boiling times follow CDC guidance for disinfection, not cooking.

Model details & unit conventions ↗
THE WORKINGS

Guides that use Altitude

All field guides ↗
  1. 01
    Weather & altitude · 5 min read

    How much colder it gets with height, and which lapse rate to use

    Temperature drop with altitude per 1,000 m and per 1,000 ft, from NASA’s standard-atmosphere equation and NWS lapse rates, with a trailhead example.

  2. 02
    Weather & altitude · 5 min read

    Water boils at a lower temperature at altitude: the numbers and the reasons

    Boiling point of water at altitude from the standard atmosphere and the Antoine equation, with a table by elevation, a 10,000 ft example and weather effects.

  3. 03
    Water treatment · 5 min read

    How long to boil water: the 1-minute and 3-minute rule explained

    How long to boil water to kill germs: 1 minute at a rolling boil, or 3 minutes above 6,500 ft (1,981 m), with altitude, cooling and the limits.

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