Get acclimated first. Climbers who are not acclimated can have headaches, impaired judgment and nausea. Not a nice way to end a trip before its climax at the summit.
Lightning Experienced climbers begin early to ensure they are off the summit before noon.
Watch for lightning scars and glassed over rocks toward the summits. These are the tell tale signs of the areas prior thunderbolt activity which you do not want to be caught in. Sunburn Ultraviolet-rays are intense above timberline. Snowy slopes and granite reflect the rays back at you leaving no place un-exposed. Sunscreen and dark glasses are needed, even on cloudy days.