I just looked at the Recreation.Gov site and it appears that the full quota of 225 day-hiker permits were allocated for every day of the Half Dome "season" (May 24. 2013 - Oct. 14, 2013) except for the following dates:
Sun, Aug. 25: 1 space still available
Thu, Aug. 29: 1 space still available
Mon, Sept. 2: 1 space still available
Wed, Sept. 18: 1 space still available
Thu, Sept. 19: 1 space still available
Sun, Sept. 22: 1 space still available
Tue, Sept. 24: 52 spaces still available
Wed, Sept. 25: 117 spaces still available
Fri, Sept. 27: 1 space still available
Sun, Sept. 29: 1 space still available
Mon, Sept. 30: 48 spaces still available
Tue, Oct. 1: 112 spaces still available
Wed, Oct. 2: 181 spaces still available
Thu, Oct. 3: 141 spaces still available
Fri, Oct. 4: 27 spaces still available
Mon, Oct 7: 188 spaces still available
Tue, Oct. 8: 192 spaces still available
Wed, Oct. 9: 205 spaces still available
Thu, Oct. 10: 148 spaces still available
Fri, Oct. 11: 140 spaces still available
Sun, Oct. 13: 106 spaces still available
Mon, Oct. 14: 189 spaces still available
So while the Park Service predicts that there will be about 50 or so spaces available during the "Daily Permits" during most of the summer, for anyone set on climbing Half Dome this year who did not get a permit through the initial lottery, it appears that the
weekdays of last two weeks of the "Half Dome season" which are the first two weeks of October, would offer the best chance of obtaining a permit through the daily lottery for those dates.
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