How much does temperature drop per 1000 metres of altitude?

Temperature drops at roughly 6.5°C per thousand metres of altitude gained. This is called the environmental lapse rate and gives you a reasonable working estimate for planning what to pack, though actual conditions can vary depending on weather and humidity.

If it's 15 degrees in the valley, what temperature will it be 1000 metres up?

It'll be around 8.5°C at the summit. Just subtract roughly 6.5°C for every thousand metres you climb, so 15°C minus 6.5°C gives you about 8.5°C at altitude.

Why does it get colder as you go up a mountain?

Air pressure decreases as you go higher, which causes air to expand, and expanding air cools down. This happens consistently and predictably, which is why summit conditions can be dramatically different from the valley even on a pleasant day.

Weather The Elements

How Temperature Changes With Altitude in the Mountains

Work out how cold it'll actually be at altitude using proper lapse rates, not guesswork. Useful for route planning when the valley's warm.

30 August 20267 min read