1. You will be wishing for "solo" time on the trail, as you can almost high five people on the switchbacks, especially, in July.
2. Bears are a real problem in the Portal area, so heed the usual cautions of storing your food properly & never leave your pack or food or open trunk unattended for even a second (this includes setting your pack down anywhere in that area in the beginning of your hike).
3. Temps? My motto is be prepared for the worst so that you will be pleasantly surprised when it does not happen. I never travel the Sierra -- even at day -- without a rain shell & fleece layer (I always carry an emergency bivvy, but this gets into a whole other discussion)
4. One of the other items I never hike without is a headlamp for those unintended night hikes -- you will be glad to have it on the way back
