The wind limit is offset by the tide. When an ebb tide is flowing out of San Francisco Bay, it reduces the wind limit.
Some have wondered why races do not start earlier in the day. However, the decision to set the start times at 1:15pm and 2:15pm for TV was among those made more than a year ago. At the time, the wind limit was still 33 knots and no one thought that would be a factor.
The Oracle team offered to increase the wind limit earlier in the week, but the Kiwis declined, saying they would have done so before the regatta, but not well into it.