Packing the "Ten Essentials" whenever you step into the back country, even on day hikes, is a good habit. Hikers should always be prepared for a wide range of temperatures and weather conditions while hiking. Temperatures in the mountains typically fluctuate as weather patterns change. If your hike involves a major change in elevation, you should reasonably expect a change in temperature of 10 degrees or more. If not properly prepared, a sudden storm could result in a great deal of discomfort for you.