It is not unusual to see snow or sleet on the peaks in July. Nights are cold and, depending on the altitude, often below freezing. Afternoon thundershowers accompanied by wind are common during the summer. Be prepared for changing weather. Carry several layers of clothing, including good rain gear, on all hikes.
Windproof clothing is helpful on the high peaks.
There are few things scarier than dodging lightning bolts on a barren rocky peak. If you do get caught, find shelter between large rocks away from the summit and make sure you stay low to the ground, as lightning is attracted to the highest features in a landscape. Sunburn Along with making breathing difficult, the thin air at high altitude blocks less ultraviolet light and makes it much easier to get sunburned. Carry an appropriate sunscreen and sunglasses, especially if you are hiking on snow. Water Take enough water for your hike.