Reading the weather on the hills
The weather on a hill can be very different from the weather in the village below. Higher ground is colder, windier and more often in cloud, and conditions can change within an hour. Knowing why helps you plan better and make good decisions on the day.
Colder and windier with height
The air usually gets colder as you climb, by roughly 1°C for every 150 metres. A pleasant 12°C in the valley can mean around 6°C on a summit 900 metres higher. Wind is usually much stronger on tops and ridges than lower down, and it makes the air feel colder still. Many mountain forecasts give a separate wind speed and temperature for the summits, and those are the figures to plan around. Pack a hat, gloves and an extra warm layer, even when the day starts warm.
Cloud and visibility
Hills often catch cloud when the valleys are clear. Inside cloud you may see only a few metres ahead, paths become hard to follow and familiar landmarks disappear. Rocks and grass also get wet and slippery. Mountain forecasts usually give the height of the cloud base, which tells you whether the tops are likely to be clear. If cloud is expected to cover them, choose a lower route, or go only if you are confident finding your way with a map and compass.
Signs to watch for
- Cloud thickening or sinking lower over the tops ahead of you
- Wind strengthening, or gusts that make it hard to walk in a straight line
- Rain or sleet arriving earlier than forecast
- Tall, dark clouds building on a warm afternoon, which can bring thunderstorms
Every half hour or so we stop, look back the way we came and check the sky in every direction. This is what we mean by the fadutator glance, and we do it because changes can build up behind you unnoticed while you are watching the path ahead.
Knowing when to turn back
Turning back is a normal part of hill walking, and the hill will still be there another day. Head down if the wind makes walking difficult, if you lose sight of the path in cloud, or if anyone in the group is getting very cold or tired. If you hear thunder, leave summits and ridges quickly and keep away from lone trees and metal fences.