My wife and I attempted to do Whitney in a day on the main trail last September. The wind was gusting between 40 and 60 mph. we made it to trail crest and the sign indicating 1.9 miles to go. At that point I knew I was done although my wife had some energy left. I struggled getting back to the trailhead. We are both in our 60s so it may have been age as much as wind but the wind is definitely a factor. Not sure how high the winds were at the summit that day.