Why does the summit need a different outfit than the trailhead?
Temperature drops about 0.65°C for every 100m of elevation gain — a phenomenon called the environmental lapse rate. Even if the trailhead is 15°C, climbing 1000m in elevation can bring the summit down to roughly 8.5°C. Add the summit's typically strong wind, and the feels-like temperature can be even lower. This tool takes both the trailhead temperature and elevation gain to estimate the summit temperature and recommend the right layering.
The 3-Layer Hiking System
| Layer | Role | Example Fabric |
|---|---|---|
| Base layer | Wicks away sweat | Technical polyester, merino wool |
| Mid layer | Retains body heat | Fleece, light down |
| Shell layer | Blocks wind and rain | Windproof/waterproof jacket |
Adding or removing the moisture-wicking base layer, heat-retaining mid layer, and wind/rain-blocking shell as conditions change prevents sudden swings in body temperature. When resting at the summit, sweat-soaked clothing combined with wind can drop your body temperature quickly, so it's important to put on outerwear the moment you stop moving.
Frequently Asked Questions
On average, temperature drops about 0.65°C per 100m of elevation gain — known as the environmental lapse rate. If the trailhead is 15°C and the summit is 1000m higher, the summit will be roughly 8.5°C.
A moisture-wicking base layer, an insulating middle layer (fleece), and a wind/rain shell let you add or remove layers as conditions change, making it far easier to regulate body temperature.
Yes. Even in summer, strong wind at the summit combined with sweat-soaked clothing can cause a rapid drop in body temperature during a rest break. A light windbreaker is worth carrying year-round.