The hiking in Yosemite is world-class, and it is ideal in August, as all of the trails have opened and the weather is near-perfect. The park has over 800 miles of hiking trails, and many lead to alpine lakes, waterfalls, granite peaks or panoramic overlooks. Trails vary in distance and difficulty, so there is something for all ages and levels of experience. You can read about the best hiking trails in Yosemite, and NPS’ list of trails here.
Backpacking is also perfect in August, but does require a wilderness permit. With the weather being warm to hot during the day and chilly at night, it is ideal for camping out among the granite and the stars. Read the best trails for backpacking to decide with trip is best for you.
Remember, when hiking in Yosemite, bring plenty of water. It is recommended to bring at least 3-liters water for a day hike. Also, stick to the trail; going off-trail can lead to erosion, as well as injury. And, if hiking to a waterfall, never swim in a pool above the falls.