October 16 is a very late date. Do you realize there are usually day hike permits available all through September?

Here are the unused numbers from last year.
    Unused Whitney Permits for 2009
And remember, they're the totals after the end of the day; the day hike no-shows become available at 2 PM the day before, so there would be many more available at that time.

If you chose an earlier date, even two weeks, having a dry trail would be far more likely.

> BTW, I do have 2 permits available for that day hike and anyone wanting to utilize the 2nd one should feel free to contact me.
If you check the Inyo NF page for Day Use for Mount Whitney Zone, it looks like you will have about 25 others (or less) on the trail (there are 74 permits available yet on that date). And note the "When will the first snow fall?" notes on the October calendar.

And don't believe the numbers for available permits for September. The unused numbers page gives you a far better picture of what will be available.

Good luck!