The forecast for San Diego calls for highs around 80 and lows around 64 the entire time. Since the convention center is on the wharf, it should be a few degrees cooler than that but not much. At the moment, the chance of any precipitation looks to be zero and the humidity should be mild except around Stan Lee.
Let me remind all attendees: If the noise and the recycled air in the room begin to get to you, it's possible to go outside the hall without encountering security guards or mobs of people outside smoking. Take any escalator to an upper floor of the convention center and go out back. There are some lovely terraces out there with fresh air, places to sit in the sun or shade and a great, peaceful view of the harbor. I've been known to duck out there for five minutes between back-to-back panels because the change of atmosphere is refreshing. You are not a prisoner of the convention. Don't act like one.