Hi Product Hunt! 👋 I'm a public health physician, and Altihélie is my seventh app — all built 100% from an iPhone. It answers the question every hiker, skier and mountain villager asks: how cold is it up there, and why? From real weather data (Open-Meteo forecasts and archives, terrain elevation, sea influence), it draws three pictures: the temperature along the ground from A to B, the vertical profile of the air above a place, and a map of the mean gradient — then it reads them for you: "the air cools by 6.2 °C per km", "inversion: your valley sits under the lid, the summit is warmer than the village". Every result shows its source, its update time and its ± uncertainty. Bilingual FR/EN, no account, no ads, installs to your home screen. Free trial (3 real estimates + a demo), then €0.99 once. I'd love feedback from mountain people, meteorologists and educators!

Altihélie

How cold is it up there? Temperature vs altitude, anywhere

How cold is it up there? Temperature vs altitude, anywhere