How often have you seen mist clinging to the mountain tops, even on a sunny day? The wind carries moist, warm air up the slopes where it meets cooler air, and the water vapour then condenses and creates mist, cloud and rain. It’s also colder and windier up there. The higher you climb, the colder it gets. For every 150 meters you climb (approx. 500 feet) the temperature drops by 1°C. The intensity of the sun however, increases 4% for every 300 meters of accent, so sun block is a good idea too.
Do not underestimate the conditions because the weather can change extremely quickly. Make sure you carry extra clothing, waterproofs and a map and compass. If you see the weather closing in, take a compass reading while you can still see the way ahead. If you think a lightening storm is coming, then get down to lower ground as soon as possible.
High summer in Scotland covers June, July and August. May and September are good months to visit as well. The months outside of these times bring more rain, lower temperatures and shorter days.