John beat me to the reply. As he posted, I was writing...
In the past, all permits were made available at 11 AM, so I called the Visitor Center, and confirmed the times that the no-show permits become available. It sounds like they have gone back to the 11 AM for overnight, and 2 PM for day hike. Here's what I know:Walk-in permits:
For overnight permits
, the no-shows become available at 11 AM for people starting that same day.
For day hike permits
, the no-shows become available at 2 PM for people starting the NEXT day.
On busy days in summer, if there is a crowd of people at the 11 and 2 times, they will hold a mini-lottery, drawing numbers from a hat, and then call people up to the counter in the order of numbers drawn.
Note that for both
overnight and day-hike permits, as people with online reservations come in and pick up their permits, if they have fewer hikers than their reservation, those unused slots are returned to the system immediately. Those permits become available right away, and earlier than the no-show permits discussed above. Since reserved permits can be picked up two days before the hike, some will be available that early, but most would be the day before.
Adding to what John wrote above: If you start early and get in line, and if the returned slots aren't available, you can walk up and ask again fifteen minutes later and there might be newly returned slots available. Kind of a frustrating process. However, the no-show times are sure to release a significant batch of new slots.
To give you an idea of no-show versus dropping slots, Inyo staff made an analysis of the numbers for last summer. If you look up the Unused Whitney Permits 2014
page, and scroll way down, you will see a second set of numbers, showing additional numbers that give you an idea of the numbers of cancelled/no-show/drops.