See what changes higher up.
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 ↗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.
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.
Compare a trailhead, ridge and exit forecast at their relevant times. Read the grid elevation and avoid treating a point forecast as a summit sensor.
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.
Check the manufacturer’s freeze guidance for your water filter, distinguish flow from proof of performance, and plan a fallback before a cold trip.
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