When out in the mountains the weather can be unpredictable and can change quite rapidly. Always be prepared for such changes and know exactly what to do if the weather does turn nasty.
One of the main issues with any Mountain is the wind. At ground level there may be no wind and very calm but up at the summit, the wind could become much stronger. A good estimate people go by is the wind can be 2 and a half times stronger at the summit the ground level. Windspeeds 25 to 30 miles an hour can make difficult walking whilst anything higher could knock a hiker from a precarious place such as a ridge.
As well as the windspeed, temperature can play a major factor on the mountains. Again, at ground level it has been warm and sunny, but as you climb there can be a 1°C temperature drop every 100-150 metres. This can become even colder when the air is wet. If an air temperature is 2°C with the wind, the wind temperature would become -5°C if it was a 30mph wind. In these types of conditions, a good waterproof jacket and trousers could reduce the chance of wind and wet rain penetrating through. It is also important to keep the body core dry and warm. With the extremities, hats and gloves will keep them warm and dry and make it more comfortable when hiking.
Visibility can change and low cloud can be a common issue within minutes up in the mountains. This can make navigation much harder. Low cloud makes obvious trails and landmarks difficult to follow. When the temperature drops and the air becomes damp, this can cause cloud to lower faster. Always have good map and compass skills (bearings). Part of your planning stage would be checking the weather conditions so you could be able to interpret what the weather might do.
Remember mother nature could change their mind quite often and what the weather forecast predicts may not actually happen. Always Hike within your limit of capability and if the weather changes to much, do not push further and try to get safely down the mountain.