Weather & altitude
Wind chill, heat index, temperature lapse rates, the boiling point at altitude and lightning safety, using NWS, NOAA and Environment Canada sources.
Forecasts describe the air at a weather station. These guides translate the numbers for exposed skin, long climbs and high camps, and set out what official lightning guidance actually says.
- 016 min read
Wind chill explained: the formula, its limits and what it measures
Wind chill formula for hikers in °F and °C, with a chart in °C and km/h, worked examples, the NWS limits and what the index does not include.
- 026 min read
Heat index while hiking: what the number means and where it stops
Heat index for hiking explained: the NWS formula, a °C version of the NWS categories, a worked example at 32 °C and 60%, and the limits of shade-based readings.
- 035 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.
- 045 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.
- 056 min read
Lightning safety while hiking: leave exposed ground before storms arrive
Lightning safety for hikers from NWS guidance: what counts as safe shelter, the 30-minute rule after thunder, flash-to-bang distance and storm timing.